Underfloor Heating - A couple of issues

[MeldrewsMate]

Looking at your kitchen floor plan, it seems evident that the water flow goes to the right hand side of your kitchen before going to the utility. Warm on that side of the kitchen but cold in the utility indicates a poor flowrate to the kitchen circuit. If you are convinced that the other d/s rooms are heating normally then I suggest taking action in the following order:-

1. Take the kitchen actuator head off its mounting, and check the pin for full movement. Compare it against that of a working circuit's pin. if the floor diagram is true then I suspect the kitchen circuit will be the right hand end of the manifold, ie furthest from the pump.
2. Check and clean the pump impellor, just a small amount of debris in here can reduce pump performance (and balance) significantly, increasing pump vibration too.
3. Disconnect the kitchen circuit and flush the pipes with clean water to remove suspended debris. You can isolate the individual circuit by turning the slot you described to horizontal, then replacing the electrical actuator with a screw-down manual cap. When finished open the individual isolators one at a time to flush debris from the manifold into a bucket.

Turning attention to the pump running-on problem, it could be that the electrical system demands the pump to continue running after the demand has been satisfied, either for a set period of time or until return temperature drops below a set figure, say 40C. That's a question for the controller manufacturer/agent.

Hope this helps.

 

[abbadon]

I spoke to the system supplier, and they confirmed run on isn't a function that they were aware of. And after fiddling with upstairs stat turned downstairs pump off...

I will certainly be investigating the flow issue as well, right now I'm more concerned about odd pump behaviour and whether boiler is running on and heating all my pipes when it should be off.

The stats for each floor seem to all correctly turn on their respective actuators, I checked this last year.

But since I have two manifolds and two wiring centres, but no mention of zone valves, it feels like the system is missing a vital control. Is there any way this could occur?

Andy

 

[cully]

The zone valves purpose is to close off flow to the manifold when demand is met, it stops the boiler and pump electrically and closes the flow of water to that manifold.
The system controller (programmer) can do the electrical part, when a stat calls for heat and the programmer time clock allows then the programmer starts the pump and boiler and conversely stops pump and boiler when demand is met. What the programmer doesn't do is close off the flow of water into the manifold.
Your combi boiler has it's own circulating pump so even with the manifold pump "power" off, there is water being circulated through the manifold (and pump) and around any open circuit. With that in mind how do you know that the pump still has power? is there a orange light on the pump casing showing pump running?
It does need an electrician who knows heating circuitry to establish where the pump gets it supply from when the ground floor programmer is off as the action on turning off the programmer then switching back on is a clue to the problem probably being in the wiring centre.
Did you get a wiring diagram from "invisibleheating" for an electrician to follow as you don't know what others before you have done!
Back to flow meters on each circuit, if I had a faulty actuator that was not closing off that loop then I could see the problem with flow.
Paul

 

[abbadon]

There is a wiring diagram that I dug out of docs on house, but despite it having two wiring centres, it only shows one pump.... So I don't know how that transfers to my system? I do have two wiring centres, but I have two manifolds and two pumps. I'll upload it shortly

Edit:
Ref knowing pump had power, (since its been turned up to three and is louder) , it was resonating the wall again, so I can hear it in most of the house, even if it is faintly... I suspect we have always had odd pump behaviour, but we haven't realised it until now, since its turned up to a setting which is loud enough to hear now. The pu itself isn't loud, just it causes this resonance somewhere else

I have attached pdf of the wiring diagram I found and a jpeg. PDF is better quality - as I say, I don't know if its as installed, and I don't know how they handled the second pump, this diagram shows only one pump.

When looking at invisible heats manual, they don't have any system diagrams with two of their manifolds featured, so they never describe a system where zoning a manifold is required - HOWEVER, they do show two port valves in relation to systems with a hot water tank or similar, or radiators and underfloor , so I guess this is similar to having a second manifold.

 

[abbadon]

Any thoughts ref that wiring? I know that there must be some additions to that since I have two manifolds and pumps but with what seems to be a lack of zone valves, is there any way with this wiring that could explain the weird behaviour with the stats and pump triggering?

 

[cully]

Tony, with regards to the water side issues I think there is some useful info. in the threads above to work through.
I would start a new thread in the electrical forum section explaining the action of the pump and appending the above wiring diagram.
The electricians are always discussing CH problems and could point you in the right direction.
Paul
ps it would be interesting to get the answer to this conundrum.

 

[abbadon]

Ok will do. I did some more fiddling again in 10 spare minutes, and if I knock off all stats upstairs and downstairs, when both pumps were running, the pair both knocked off. But then only bringing a downstairs one back turns both pumps back on. It's not possible as far as I can tell to bring the upstairs pump on by itself. I'll link to electrical based thread from here once I get time to start it, maybe later or tomorrow. Andy

 

[abbadon]

For anyone who ends up here, this is the thread in the electrical forum, albeit a year on from the last post here.

https://www.diynot.com/diy/threads/underfloor-heating-controls-a-conundrum.512261/