'Nest' Wireless Thermostat with Firebird Super Q Boiler

PaulOS69

Just got the 'Nest' wireless thermostat fitted to my boiler yesterday. The 'Nest' system has a 'Heat Link' base station connected directly to the boiler and the thermostat out in the room you use regularly.

I noticed that the guy that installed this, installed the 'heat link' directly to the FCU on the wall above the boiler. I ran the boiler last night and the boiler runs perfectly until it reaches the temperature its supposed to reach. Because he wired it with a splice into the switch it shuts off the boiler but also shuts off the pump over-run. The residual hot water left in the is now stuck there and doestnt get a chance to move until it switches back on and at that stage has cooled down.

I wonder has this the potential to cause damage? Its not the most efficient way to run. Has anyone come across this, maybe a relay from the mains onto the pump to runoff the excess hot water? any thoughs??

Billy Bunting

It will cause problems with hi limit stat tripping with residual heat in boiler.

Wearb

It would not have been much extra work to wire it correctly. Get him back. Or at least ask him if there was a good reason why he bypassed the pump over run.

PaulOS69

Wearb: He told me that his company only install directly to the boiler (eg programmer or the like). In my case the FCU switch. Any additional wiring within the boiler, by-passes or work arounds, are the responsibility of the customer. Well thats the response I got when I rang him today having only last night realising it was a quick connection he made which shuts the whole system off (boiler & pump).

Billy: It didnt trip last night anyhows. Just wrecks my head the thought that theres wasted hot water stuck in the boiler. Have you encountered this?

Wearb

I wouldn't worry too much about heat loss it is most likely very little.

The company should have informed you of the limitations of their wiring. It will probably get you nowhere, but complain to them that they have interfered with the economical running of your system and left you open to possible nuisance lockouts. Tell them the way you want it wired and if they are not willing to do that, then come back and remove it and refund you.
How far you get with all of this, depends on the company and how far you are willing to take it. It will not be worth going to a lot of trouble, as it is a relatively easy fix.

PaulOS69

Wearb: thanks for that, yea its probably minimal compared to the savings the thermostat will make. Id be happy enough once I know the boiler/pump not getting damaged. Might just leave it and see how it performs over the next few days. There a local guy here who specialises in fitting these Nests so might get him out if i'm not happy. Just interested to see if anyone has one of these fitted to the relatively simplex 'Super Q'?

17larsson

That's a ridiculously lazy approach. Some of these guys think about nothing but getting finished the job as quick as possible

ctlsleh

i have a couple of nest installed and was reading your above point about how they are wired. basically mine control the power to the boiler and to the valves, when they switch off the power to the boiler and the valves and the boiler basically switches off the pump at the same time......is there a better way to wire them?