Bolier firing, but no hot water!

[Crosswire]

Called to a large house with two boilers and two cylinders.

An electrician had been round and altered the wiring centre and now the house has lost it's hot water.

The boilers were firing, the pressure was going up and then they cut out (due to some safety mechanism I suppose)

The hot water pipes leaving the boiler were hot, and the pumps were pumping, but the water reaching the taps was lukewarm at best.

I turned on the megaflows so as to leave them with some hot water, but for the life of me couldn't find the fault, after spending 2 hours on it.

Pretty sure it is an electrical/wiring problem, but couldn't find it.

What am I missing? Please help, as have to go back on Monday and am not looking forward to it

P.s. all valves are standard 2 port valves, and the underfloor heating is incorporated as well

 

[Deleted member 9648]

Why dont they call back the electrician who appears to have cocked it up?......Check the HW valves are opening when the tank stats are calling,presumably they are not.If not check you are getting power to the valve motors,......power faulty valve.no power trace the wiring back to the wiring centre.

 

[Crosswire]

Think they fell out with him.

Got power to valve motors, pipes are hot on both sides of the valve so appear to be opening. Got power in and out of the cylinder stat, so assume they are calling. I'm totally out of ideas.

 

[truckster]

Sounds like the primary side is working so I would look at the cylinder stats, are they wired correctly? NO/NC swapped?

 

[Deleted member 9648]

If the valves are open and the pumps are running and the boilers fire it should be heating the tank coils....I would just run through the electrics functionality.ie,programmer on HW,tank stat satisfied=valve shut,boiler and pump off. Turn up tank stat=valve open,boiler and pump fire......if that happens suspect plumbing issue.

 

[bob22]

Hi crosswire, could be a plumbing problem, when you say that the pressure rises is that the pressure in boiler? If so could be a faulty expansion vessel/tank, could also be a faulty pump or air in the system (plumbers problem).

 

[Crosswire]

Yeah the pressure in the boiler, according to the home owner, although it didn't do it when I was there. Water did dribble out of the overflow though.

 

[Des 56]

Quote
An electrician had been round and altered the wiring centre and now the house has lost it's hot water.

For what reason did they call the electrician who altered the wiring centre initially

Are being asked to fix a secondary problem
What was the initial reason for him to carry out these alterations

 

[truckster]

Not something simple like the valves have been swapped so the roomstat is operating the water and vice versa, might not be obvious on UFH, or the valve heads have been removed and not clicked back on fully but you say that water appears to be flowing through the valves. If the sparky altered the wiring I can't see as it would be a plumbing prob.

 

[Crosswire]

Quote
An electrician had been round and altered the wiring centre and now the house has lost it's hot water.

For what reason did they call the electrician who altered the wiring centre initially

Are being asked to fix a secondary problem
What was the initial reason for him to carry out these alterations

The wiring was a mess apparantly, with cables wrapped round hot pipes, and all jammed in the side of the wiring centre with the cover hanging off etc... They got him to reroute all the cables in trunking and generally tidy it up (which he appears to have done), but hot water stopped working...

 

[Apollo]

The primary pipe you say is hot on the other side of the 2 port valve - this doesn't mean that its working this could be hot by conduction.

Try the heat at the primary return or better still the HW outlet on the cylinder. you mentioned water coming out of the overflow is this on the Cold water cistern or feed and expansion tank (later is the smaller of the 2) if its the cold water cistern what is the temperature of the water?

You said they don't have hot water but do they have water out of the HW taps? if they do there is nothing wrong with the plumbing and its down to the changes at the wiring centre that the electrician undertook.

if the heating system is working? trace the cables back and change the wiring over for the HW side. if they then have hot water you know the 2 port valve is the problem be it the wiring or the motor itself. Just becasue you have power doesnt mean its operational (sorry if that sounds like teaching you to suck eggs)

Hope you get it sorted.

 

[Crosswire]

Thanks for all the replies. Just to update...


On my first visit I found a neutral out of one of the valves. I put it back in and went to the hot water tap. It came out lukewarm, so I assumed that this was not the only fault. I didn't mention this in the original post as itdidn't appear ( at the time) to be the problem.


However, whilst driving to the job on Monday morning, I got a text to say that the hot water was now fine!

I can only assume that I didn't wait long enough for the hot water to come through the system or something, on my initial Friday afternoon visit and spent ages trying to fnd a fault that wasn't actually there... (numpty)


Despite having spent a weekend worrying and reading up on central heating systems it all turned out fine in the end , it seeems !


Anyway thanks all,
Crosswire

 

[ukzmisr]

I had a problem similar to this. The plumber replace a direct valve in the air cupboard.

 

[hanky-pankysex]

Sounds Like the megaflows need recharging as they don't have a seperate expansion vessel it actually says on the side of the cylinder how to do it.