Do I need zone valves?

[Mat1980]

We've just had a Vaillant 830 installed with radiators upstairs and a single zone ufh manifold downstairs. Plumber can't do the wiring so I'm trying to figure out what's going on before I get someone else in.

Everything I've read tells me I should be seeing 2 zone valves but this isn't the case.

Without the zone valves how are our 2 thermostats going to work??

 

[ianmcd]

yes you will need zone valves

 

[ericmark]

A zone valve does not need to be some thing like this

this

is also a zone valve, the first is digital i.e. on/off and has a micro switch built in, the second is analogue and uses wifi to transmit its state.

I had the discussion with my plumber, with all motorised TRV heads why do I need a traditional motorised valve, and I decided since my granny flat is rarely used it was better to have the traditional motorised valve so there was a definite off. Also there was a hard wired switch telling the system when off, I was having problems with reverse flow, but could have simply used one way valves.

I could also switch pumps on/off, which was the way it was controlled before I bought the house. The problem is I have needed to fit an adaptable box with relays

due to lack of micro switches in the motorised valves, a real pain, I would have preferred to have one pump and two motorised valves, but the valves work pump and relay and relay works the boiler. However my boiler is simple on/off.

So with a boiler which can modulate, you want analogue controls, you don't want to turn off/on to control temperature, you want up/down, to control when heated on/off to control how much heat up/down. And I struggled with this with last house, the wall thermostat used a mark/space ratio to control boiler output which was completely unsuitable for the boiler, every time a boiler is turned off any heat in boiler goes out of flue, and when turned on again it will turn on flat out, so all the cleaver modulation may as well not be there.

So back to basics, we put the on/off wall thermostat in a entrance level room with no doors to outside, no alternative heating, and normally kept cool, and it's job is simply to stop boiler cycling when weather warms up, it does not control room temperature, if we want a wall thermostat to control room temperature we use an analogue type like opentherm to tell boiler to modulate output.

The same applies to electrical systems, we start with design, then we have installation, followed by inspection and testing, with electrics we even have three signatures, but the design is done before the installation not after. So if designed for wifi control that is what you need to fit. I am sure the plumber was not doing some modern art, and he was following some standard design, question is what standard design? Simple answer is ask him, get a copy of the design which will include both plumbing and wiring.

 

[Mat1980]

The same applies to electrical systems, we start with design, then we have installation, followed by inspection and testing, with electrics we even have three signatures, but the design is done before the installation not after. So if designed for wifi control that is what you need to fit. I am sure the plumber was not doing some modern art, and he was following some standard design, question is what standard design? Simple answer is ask him, get a copy of the design which will include both plumbing and wiring.

I wish my plumber was like this. There is no design. Every time he does one job I end up with two jobs trying to fix the things he has decided not to check. I'm at my wits end.

In this case he has installed no zone valves and tee'd off to the rads somewhere under my newly tiled bathroom floor.

The workaround for now seems to be a zone valve for the UFH downstairs and smart TRVs for the rads upstairs. Then it's just a case of chasing the zone valve cable from downstairs up to the loft. That's the only thing I can think of that doesn't involve pulling up the floors.

What do you think?

 

[ianmcd]

The workaround for now seems to be a zone valve for the UFH downstairs and smart TRVs for the rads upstairs. Then it's just a case of chasing the zone valve cable from downstairs up to the loft. That's the only thing I can think of that doesn't involve pulling up the floors.

Your UFH may or may not require a zone valve , depends what system you have ,

 

[Mat1980]

This is what I have, https://www.theunderfloorheatingsto...anifold-pump-pack-with-esbe-mixing-valve-unit

Single zone downstairs, wet

 

[ericmark]

I can't say how your UFH works, there is often a manifold and pump, the basic idea is water circulates around the UFH and as it cools more hot is added I seem to remember some where around 27°C in essence too cool to reheat fast so never turned off, which in some ways helps the boiler modulate correctly as never turned off, however that is why I don't like UFH it takes too long to heat and cool, OK as an addition, but not as only form of heating as just morning sun can mess it all up, in any room with a window that catches morning sun you want central heating that responds fast. But in essence all you do is control the temperature of circulating water, which is all part of the manifold.

Upstairs the TRV likely will do all you need, programmable ones like the eQ-3 seen only cost £10 without blue tooth, £15 with blue tooth, so upstairs will also look after its self

So the only control required is to turn off boiler as summer arrives, to stop cycling, I have never looked into IFTTT switching, based on weather reports, but seems likely possible.

This is what I was considering in first post, it is down to how you planned to use it. We call the people who design central heating systems heating and ventilating engineers, to my mind engineer means trained to level 5 or above, and they have the skill to take into account sun through windows, and design the system so it can respond to weather changes, my last house was easy, open plan, sun was not a problem, mothers house, bay windows and the sun could cause 32°C in the room until I fitted electronic TRV heads. In her house speed of response was critical, when sun came out needed radiators cold within ½ hour, my house it could take 3 hours to cool down.

All houses are not the same, and heating needs to suit the house, our dinning room here could have UFH, the living room no way.

 

[ericmark]

This is what I have, https://www.theunderfloorheatingsto...anifold-pump-pack-with-esbe-mixing-valve-unit

Single zone downstairs, wet

I assume back ground heating only, that is a great idea when you also have radiators with TRV's fitted to control room temperature, it reduces size of radiator required, but unless an open plan house there must be some thing else?

 

[Mat1980]

I assume back ground heating only, that is a great idea when you also have radiators with TRV's fitted to control room temperature, it reduces size of radiator required, but unless an open plan house there must be some thing else?

Just this downstairs as it's open plan, TRVs and rads upstairs.

The UFH is set to about 40degrees at the manifold but at the moment I don't have a way to fire up the pump and call for heat.

 

[ericmark]

So take a sanaro and consider if it will work. So if you fit a Hive thermostat down stairs this can link to upstairs TRV heads, and it in turn can fire up boiler and the two pumps, but one problem is the thermostat will not turn off ground floor if up stairs calls for heat then down stairs will over heat.

So the question is if that sanaro is likely?

In my house up stairs always hotter than down stairs. So in my house one could forget up stairs so no need for a TRV with a link to main thermostat cheap eQ-3 would do. You know your house, I don't, so trying to give pointers. It is possible you can simply forget upper floors and let them look after them selves.

 

[Mat1980]

Thanks man.

Yeah the issue I can see happening is that without some sort of smart TRV system I won't be able to fire up the boiler if the UFH isn't already calling for heat.

Now the question is which system for the TRVs, apparently the nest I bought for upstairs isn't going work.