Combi boiler- How water not that hot anymore

[Geordie Spark]

Ok, but where will the isolation valve likely to be. If the boiler is upstairs and the shower is also, would it be likely for the pipes to run in the loft or under the floor. The shower is directly above the bath so i would assume that the hot and cold feed is tapped off the supply to the bath or vice versa. Could I just isolate at the main stop cock and remove the taps?

Trust me ..... you don't need to do any of this ...... we are assuming that your shower is NOT an electric one and runs off the boiler. Is that right??

If so, then it really is just because of the water coming in to the house being so much colder at this time of year.

While I admit I don't know everything there is to know about plumbing, gas & boilers etc. I did work as a Heating Engineer until I retired.

 

[i=p/u]

Its all about knowing how these things function the path it take and what this does... Use next doors

 

[graeme210375]

Ok, but where will the isolation valve likely to be. If the boiler is upstairs and the shower is also, would it be likely for the pipes to run in the loft or under the floor. The shower is directly above the bath so i would assume that the hot and cold feed is tapped off the supply to the bath or vice versa. Could I just isolate at the main stop cock and remove the taps?

Yep, just turn the stopcock off, turn taps on to drain the pipework, then remove taps/shower. This will not effect your central heating as , although it is heated via the same boiler, the c/h is a sealed system. The hot & cold come directly from your mains water (isolated via stopcock) the boiler heats up the water and feeds it to your hot taps and your cold taps are fed directly from the mains water. Your c/h is topped up via the filling loop (this will be the only time it uses mains fed water) then just circulates the same water within its own sealed system. If you are using taps fed shower, limescale/rust build up on the incoming hot filter at the taps will reduce the flow of hot water. On the majority of repairs I've done for this problem, that simple task fixes the problem.

 

[Geordie Spark]

Yep, just turn the stopcock off, turn taps on to drain the pipework, then remove taps/shower. This will not effect your central heating as , although it is heated via the same boiler, the c/h is a sealed system. The hot & cold come directly from your mains water (isolated via stopcock) the boiler heats up the water and feeds it to your hot taps and your cold taps are fed directly from the mains water. Your c/h is topped up via the filling loop (this will be the only time it uses mains fed water) then just circulates the same water within its own sealed system. If you are using taps fed shower, limescale/rust build up on the incoming hot filter at the taps will reduce the flow of hot water. On the majority of repairs I've done for this problem, that simple task fixes the problem.

I think you need to think very carefully about this in relation to the OP's problem.

The OP has plenty of water coming from his shower, the problem is that at this time of year it isn't hot enough for him.

Reducing the flow - whether by turning the stopcock or isolating valve down or by a build-up of limescale/rust would actually IMPROVE his situation !!!

 

[graeme210375]

Yep, just turn the stopcock off, turn taps on to drain the pipework, then remove taps/shower. This will not effect your central heating as , although it is heated via the same boiler, the c/h is a sealed system. The hot & cold come directly from your mains water (isolated via stopcock) the boiler heats up the water and feeds it to your hot taps and your cold taps are fed directly from the mains water. Your c/h is topped up via the filling loop (this will be the only time it uses mains fed water) then just circulates the same water within its own sealed system. If you are using taps fed shower, limescale/rust build up on the incoming hot filter at the taps will reduce the flow of hot water. On the majority of repairs I've done for this problem, that simple task fixes the problem.

I think you need to think very carefully about this in relation to the OP's problem.

The OP has plenty of water coming from his shower, the problem is that at this time of year it isn't hot enough for him.

Reducing the flow - whether by turning the stopcock or isolating valve down or by a build-up of limescale/rust would actually IMPROVE his situation !!!

I think you have misunderstood or misread my post. Build up of limescale or rust on the filter located on the inlet to mixer taps (both hot and cold) will reduce flow to the taps / shower. Now what I'm getting at if the filter to the hot water feed of the mixer / shower taps is blocked, then you will get a reduced hot flow in relation to the flow of cold water, thus you will need to open the hot tap further to get the desired temperature. I'm simply suggesting he checks this. It will take less than 5 mins. I'm not suggesting a boiler overhaul.
Don't think the OP has mentioned if the flow from his shower is reduced or not.

With modern boilers, limescale and rust are beneficial to no one. They block heat exchangers and cause boilers to overheat and lock out.

NOTE TO OP - if ur still following this, and decide to try cleaning the filters on the taps, turn the power to the boiler off once the stopcock is off, before drawing remaining hot water to drain.

 

[Geordie Spark]

I think you have misunderstood or misread my post. Build up of limescale or rust on the filter located on the inlet to mixer taps (both hot and cold) will reduce flow to the taps / shower. Now what I'm getting at if the filter to the hot water feed of the mixer / shower taps is blocked, then you will get a reduced hot flow in relation to the flow of cold water, thus you will need to open the hot tap further to get the desired temperature. I'm simply digesting he checks this. It will take less than 5 mins. I'm not suggesting a boiler overhaul.
Depends where in the country the OP lives. The temp down here is around 6 degrees ay the moment, which certainly won't be enough to reduce the water temp enough to effect the boiler to that degree.

With modern boilers, limescale and rust are beneficial to no one. They block heat exchangers and cause boilers to overheat and lock out.

Agreed !!!

 

[telectrix]

With modern boilers, limescale and rust are beneficial to no one. They block heat exchangers and cause boilers to overheat and lock out.

always wondered why the ex-wife locked out. now i know. should have given her a good descaling.
​

 

[chris murphy]

I think you have misunderstood or misread my post. Build up of limescale or rust on the filter located on the inlet to mixer taps (both hot and cold) will reduce flow to the taps / shower. Now what I'm getting at if the filter to the hot water feed of the mixer / shower taps is blocked, then you will get a reduced hot flow in relation to the flow of cold water, thus you will need to open the hot tap further to get the desired temperature. I'm simply suggesting he checks this. It will take less than 5 mins. I'm not suggesting a boiler overhaul.
Don't think the OP has mentioned if the flow from his shower is reduced or not.

With modern boilers, limescale and rust are beneficial to no one. They block heat exchangers and cause boilers to overheat and lock out.

NOTE TO OP - if ur still following this, and decide to try cleaning the filters on the taps, turn the power to the boiler off once the stopcock is off, before drawing remaining hot water to drain.

"Hello graeme210375 and adammid",


I would agree with Geordie Spark in ALL that He has written about this question about the Hot Water from a Combi Boiler to a Shower / Shower Valve being not as Hot during the last few Weeks.

It is VERY likely that this is because the temperature of the Incoming Mains Water is MUCH lower at this time of Year - without even Testing My Mains Water I know from experience that it will not be much more than 3 or 4 Degrees Centigrade - possibly only 2 Degrees.

MOST Combi Boilers are only capable of raising the temperature of the Mains Water by 35 Degrees at a Flow Rate of either approximately 9 Litres per Minute for the Lower Input / Output Combi`s - OR 12 Litres per Minute for the Higher Input / Output Combi`s.

SO:

If the incoming Mains Water in early November was for example 8 to 10 Degrees [Guesstimate] and the Combi is only capable of raising the Water temperature by 35 Degrees - theoretically the Hot Water Temperature would be 43 to 45 Degrees - this is quite Hot and would require mixing with the Cold Mains Water at the Shower - hence a reasonable Flow Rate and acceptable Temperature.

NOW / Cold Autumn / Winter Days & Nights:

Mains Temperature = 2- 3 or 4 Degrees - Heated by 35 Degrees = 37 - 39 Degrees - This is a VAST difference in Hot Water Temperature for Showering purposes !

While still too Hot to use the Hot Water only - even a slight introduction of Cold Mains Water will cause the Shower Temperature to be VERY noticeable as `Not anywhere near as Hot as previously` - as seems to have occurred in the OP`s enquiry.


Geordie Spark has stated exactly these points in His answers.


graeme - If the OP would like to follow your advice regarding the Filters - regarding your advice that this is `Only a 5 Minute Job`:


IF the OP has a good quality Shower / Shower Valve there would be Filter Inserts to the Inlets.

IF the Shower Valve is NOT built into the wall it should be possible to access these Filters - that may be a `DIY job` ? - If the OP is an Electrician He would obviously be professional in the use of Adjustable Spanners / Pump Pliers etc. - to ensure that the Inlet connections are NOT either Over-tightened / Cross Threaded afterwards.

BUT - I would NOT advise a person who was NOT a Tradesman / `On the Tools` worker to try disconnecting a Shower Valve connections - removing Filters which may be `Stuck in`etc. - as I have seen connections to Shower Valves ruined by people who wanted to do a `DIY job` on repairing the Shower.

Apart from High Quality Bath Shower Mixer Taps / Bath Mixer Taps you will very seldom find Filters on Bath Mixer Taps / Bath Shower Mixer Taps - unless there are Flow Limiters with built-in Filters fitted to the Inlet Pipework.

These are not often found in all but the Newest of Homes unless the Plumbing is either fairly New or the Flow Limiters / Filters have been fitted for the reason of limiting the Flow from the Taps / other outlets in order to supposedly `Boost` the Flow to other Taps/ Outlets.


I am a Heating Engineer - Qualified Plumber and Gas Engineer / Heating - Plumbing and Gas Contractor - just as a reference to where My knowledge and Opinions come from.


Regards,


Chris

 

[chris murphy]

Thanks guys. The boiler was actually replaced a few months ago as the old one had a dodgy diverter valve. When the hot tap was turned on, the radiators came on too. My girlfriend, who lived in the house before me, thought that was normal and had been doing it for a year or so. When I moved in and realised that wasn't right we got the plumber to come and he replaced the boiler.

Back to the current issue with colder hot water. I have turned the hot water stat on the boiler to max which is 60c but doesn't make much difference. it makes sense though, when you say the water entering the property is colder and therefore the boiler has to work harder to heat it up, but I would have thought that 60c is 60c and if thats what my stat says then that is how hot the water should be that comes out of the tap.

Yes i understand that the boiler has to work harder, but it should still be the same temp that comes out of the tap. It just means the boiler works harder, my gas bill goes up but i still get nice warm showers.

"Hello adammid",

Please read My Post in reply to graeme / yourself for the details about what I agree with Geordie Spark is VERY likely to be the cause of the VERY noticeable drop in the Hot Water Temperature at your Shower.

Regarding your comment above about the supposed 60 Degree Hot Water Temperature - IF You have a `Normal Sized` [Gas Input / Output to Water] Combi Boiler - it will undoubtedly ONLY be able to Raise the Temperature of the Incoming Mains Water by approximately 35 Degrees - at a Flow Rate of only approximately 9 Litres per Minute.

Whatever is shown on the Combi Hot Water Thermostatic Control I doubt whether the Combi would Heat the Mains Water to 60 Degrees with a 9 Litre Flow Rate even in the Summer when the Mains Water is usually approximately 18 to 20 Degrees - a 35 Degree rise to that would still only equal approximately 53 to 55 Degrees absolute MAX.

Although this is definitely as Hot as You would EVER need Hot Water to be for Dish Washing etc.

As I stated in My other / more detailed post the Incoming Mains Water at this time of the Year would only be approximately 2- 3 or 4 Degrees - MUCH lower than even in October / early November - So you are probably only getting about a 37 - 39 Degree Hot Water Temperature.

I am afraid that You have NO Option but to `Govern Down` the Hot Water Flow to the Shower Outlet - enabling the Water to Flow through the Combi at a Rate which it CAN raise the Temperature to an acceptable level - I would suggest that You just have the Shower Flow adjusted on the Shower Valve.

This WILL mean that You have to put up with less Water Flow during the Autumn and Winter Months.

Sorry that I cannot give You any better `News` regarding this - Geordie Spark is correct in all that He wrote advising You on this.


Regards,


Chris - Heating Engineer - Qualified Plumber and Gas Engineer / Heating - Plumbing & Gas Contractor.

 

[cobrauk]

My way which is to just not turn on the shower flow fully works I do it everyday and I still have a good flow of water as we have good pressure in the first place

 

[chris murphy]

My way which is to just not turn on the shower flow fully works I do it everyday and I still have a good flow of water as we have good pressure in the first place

"Hello cobrauk",


That is what I advised to OP / adammid to do when I wrote this:


I am afraid that You have NO Option but to `Govern Down` the Hot Water Flow to the Shower Outlet - enabling the Water to Flow through the Combi at a Rate which it CAN raise the Temperature to an acceptable level - I would suggest that You just have the Shower Flow adjusted on the Shower Valve.

This WILL mean that You have to put up with less Water Flow during the Autumn and Winter Months.


Regards and Happy Christmas,

Chris

 

[Geordie Spark]

My way which is to just not turn on the shower flow fully works I do it everyday and I still have a good flow of water as we have good pressure in the first place

Yes ... that's quite right. By doing this, what you're doing is "Governing Down" the water flow through the boiler to a level that it can cope with

 

[cobrauk]

"Hello cobrauk",


That is what I advised to OP / adammid to do when I wrote this:


I am afraid that You have NO Option but to `Govern Down` the Hot Water Flow to the Shower Outlet - enabling the Water to Flow through the Combi at a Rate which it CAN raise the Temperature to an acceptable level - I would suggest that You just have the Shower Flow adjusted on the Shower Valve.

This WILL mean that You have to put up with less Water Flow during the Autumn and Winter Months.


Regards and Happy Christmas,

Chris

I posted in post number 3
"My bet is that the cold water feeding the boiler is that much colder, electric showers are the same this time of the year, you just need to slow the speed of the water a bit by not having the shower not running at full pressure to help combi, well that's what I do."

Which is what the final conclusion has ended up being isn't it ? lol

Merry Christmas to you all

Read more: http://www.electriciansforums.net/c...-how-water-not-hot-anymore.html#ixzz2FVEiHtOd
​

 

[Geordie Spark]

I posted in post number 3
"My bet is that the cold water feeding the boiler is that much colder, electric showers are the same this time of the year, you just need to slow the speed of the water a bit by not having the shower not running at full pressure to help combi, well that's what I do."

Which is what the final conclusion has ended up being isn't it ? lol

Merry Christmas to you all

Read more: http://www.electriciansforums.net/c...-how-water-not-hot-anymore.html#ixzz2FVEiHtOd
​

Yep ... I posted the same thing about the same time

Nice to know that we're all (well .... most of us) in agreement !!!

 

[chris murphy]

I posted in post number 3
"My bet is that the cold water feeding the boiler is that much colder, electric showers are the same this time of the year, you just need to slow the speed of the water a bit by not having the shower not running at full pressure to help combi, well that's what I do."

Which is what the final conclusion has ended up being isn't it ? lol

Merry Christmas to you all

Read more: http://www.electriciansforums.net/c...-how-water-not-hot-anymore.html#ixzz2FVEiHtOd
​

"Hello again cobrauk",


Please don`t misunderstand My comments - I know that You and Geordie Spark had already suggested exactly what I wrote about turning down the Water Flow through the Shower / Combi Boiler.

I was not trying to be funny when I replied to You earlier Today - I was just responding to write that I had advised the OP / adammid exactly the same thing.

Although WE are replying to each other I notice that HE has NOT responded to Us after reading from THREE of Us that it is almost undoubtedly a Mains Water Temperature issue - Not even a "Thanks".

I suspect that because He has not read what He wanted to read from Us that He either thinks that We are wrong or simply cannot be bothered now that there seems to be no `Remedy` to the situation.

Sometimes it seems that Whenever I go to the lengths of writing VERY Long messages - I / We don`t receive even an acknowledgment from the OP - let alone a `Thank You` !

As has often been stated in the past - on here and other Forums - Some People simply don`t appreciate Us trying to Help.

Regards,

Chris