Nest wiring help - not controlling boiler on/off unless hot water set to heat

Stevomac · Apr 1, 2018

1st post and I’m not a heating engineer/electrician so apologies for lack of proper terminology.

It’s a long story but in essence I had a new conventional boiler replace 2 years ago (Worcester Bosch 28i) and had issues with way heating engineer wired up the new rf thermostat.

Decided to fit a nest to make life simpler. He has installed the nest and now I only seem to get heating when the thermostat is set to run both hot water and heating. Once the water in the tank gets to temp it then switches off and I have no heating.

The thermostat is controlling the hot water and the heating actuator valves upon command (on/off). However when you switch the heating only ON the valve opens up but the boiler does not switch on (will only come on if I also set HW to come on).

The heatlink over ride button does not appear to switch on the boiler either.

Anyone got any thoughts on what he has done wrong. I’m at my wits end. It’s the 3 time he has attempted to fix it.... I’ve persevered with him as it should be his job to fix. I’ve spend plenty. But not sure he knows what he’s doing.

The Ghost · Apr 1, 2018

I think some pictures would help enormously here if you can manage that?

Octopus · Apr 1, 2018

Maybe go on the Nest site and find an approved installer?

Jamie' · Apr 1, 2018

If you've paid a so called heating engineer to install it and it isn't working as it should,get the fella back in to sort it out. If he has no clue then he should be paying someone to sort it out.

Leesparkykent · Apr 1, 2018

Take some pictures of the cylinder cupboard/motorised valves and the wiring and it might give us a bit of a clue.

Stevomac · Apr 1, 2018

It’s my intention to get him back... for 3rd attempt at fixing my controls. I’m loathed to pay someone else - end of the day it’s his job but I’m at my wits end with him. But you don’t put your can in the garage to pay a mechanic to nearly fix your car. Putting nest in was meant to fix the problem at the cost of £220. Will try to post photo.

Stevomac · Apr 1, 2018

[ElectriciansForums.net] Nest wiring help - not controlling boiler on/off unless hot water set to heat

This is the set up. 2 actuators. Bottom one for heating - goes off /on when commanded to by thermostat but doesn’t switch boiler on so no heating... but if I then switch the HW to ON on the thermostat the boiler switches in and heating comes on.

Leesparkykent · Apr 1, 2018

The HW valve looks like it could be a momo valve (motor on, motor off) if thats the case this valve requires different connections than a regular spring return valve. The heating valve should have voltage on the orange which fires the boiler when the valve is open/micro switch closed (when calling for heat). TBH an electrician who's familiar with heating wiring would take only a few minutes to determine what's wrong using a multi meter. It's either wired wrong or the valve isn't closing the micro switch in the valve.

suffolkspark · Apr 1, 2018

that really a lovely simple set up, its obviously possible a microswitch in a valve isn't making but id assume they are new so unlikely? id pay somebody else to sort it (probably an hour or 2) and save my sanity!

FatAlan · Apr 1, 2018

About to have a new heating system fitted. Must admit I’m of a mind to steer clear of smart systems and stick to hard wired thermostats and old fashioned timers. Bad enough already farting around with various other Wi-fi devices at the moment to contemplate additional Wi-fi issues with heating. But then again I am over 50!

buzzlightyear · Apr 1, 2018

Stevomac said:
Putting nest in was meant to fix the problem at the cost of £220. Will try to post photo

may be you should have got a hive engineer in the beginning ,or have you been stung.

buzzlightyear · Apr 1, 2018

FatAlan said:
About to have a new heating system fitted. Must admit I’m of a mind to steer clear of smart systems and stick to hard wired thermostats and old fashioned timers. Bad enough already farting around with various other Wi-fi devices at the moment to contemplate additional Wi-fi issues with heating. But then again I am over 50!

I call it f**king lazy ness sat holding your smart phone turning up the heat ,cant be bothered, moving the body .finger first !it what be long before they put one on the remote of the tv.

123 · Apr 1, 2018

Leesparkykent said:
The HW valve looks like it could be a momo valve (motor on, motor off) if thats the case this valve requires different connections than a regular spring return valve. The heating valve should have voltage on the orange which fires the boiler when the valve is open/micro switch closed (when calling for heat). TBH an electrician who's familiar with heating wiring would take only a few minutes to determine what's wrong using a multi meter. It's either wired wrong or the valve isn't closing the micro switch in the valve.

The HW valve is a Myson, and as far as I'm aware they don't make momo valves (isn't that just a Sunvic thing?)

123 · Apr 1, 2018

buzzlightyear said:
I call it f**king lazy ness sat holding your smart phone turning up the heat ,cant be bothered, moving the body .finger first !it what be long before they put one on the remote of the tv.

If it was laziness then an RF Stat is a far cheaper solution. The Smart Stat's are far better and more economical for modern living.

davesparks · Apr 2, 2018

So you’ve employed a plumber to work on your electrics and you’re surprised it doesn’t work properly?

You might as well employ a gardener to change the brake pads on a car.

Nest wiring help - not controlling boiler on/off unless hot water set to heat

Stevomac

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The Ghost

Octopus

Jamie'

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Leesparkykent

Stevomac

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Stevomac

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Leesparkykent

suffolkspark

FatAlan

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buzzlightyear

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buzzlightyear

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123

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123

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davesparks

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