UFH - EvoHome and reluctant plumber

[eightiescalling]

Hi All,

We're having an extension put in with wet under floor heating for the kitchen - the plumber is suggesting this is done with 3 piping runs to improve the effectiveness of it.

I've been using the EvoHome setup across the rest of the house for a couple of years and very happy with it - the flexibility between rooms, zones, API that can be used separately to the apps etc.

The plumber however has never dealt with EvoHome and pushing me towards HeatMiser claiming cost but then also saying it will be the same number of controllers on the manifold either way. I'd rather stick with one controlling system overall.

I'm not familiar with the piping/manifold setup for UFH and I must admit still struggling a bit on the EvoHome vs HeatMiser parts. I was wondering whether those here that know way more than me (pretty much everybody!) could help me on the difference between the two cost wise and whether that difference gets much worse based on the 3 pipe runs.

Thank you!

P.S. Irrespective of any answers on this one, thanks to everyone that does help and answer threads on this forum - it's been a mine of information!

[rvb99]

Since you have a single zone ( just the kitchen) the simplest and cheapest is to wire the ufh 3 manifold valves in parallel to a bdr91 also with the ufh circulation pump ( use a connection box) . You will also need a room stat such as YRf87 . This way when the kitchen zone calls for heat the bdr will open the manifold valves and kick off the circulation pump.
We use a HCC 80 ufh controller which works flawlessly for multiple zones but you only need this if you have 2 or more ufh zones to control.

[BuxtonJim]

Completely agree with rvb99. This is precisely the route we went with a single zone UFH - works flawlessly. Didn't even need an additional sensor as the Evotouch display was already sited there.

[eightiescalling]

Thanks for the feedback guys - that's exactly what I needed.

I'm going to be needing some more HR92s anyway and while I have a DTE92 going spare that would do the same job, I do prefer the YRF87 - and it's passed the WAF test already in the lounge where there are a few rads tied to a single zone.

rvb99 - Are there any downsides to hooking the 3 valves up in parallel? Presumably it assumes all 3 runs are equally spread etc. Assume there are no issues with the power draw from 3 valves for the relay rather than 1?

[rvb99]

Power draw from the manifold actuators and pump is negligable. In any ufh you should ensure the pipe circuit lengths are more or less the same within a few metres.

[bruce_miranda]

You don't even need to invest in electronic actuators. Just leave the manifold manual ones on. As long as each circuit run is about the same length and they are all serving the same zone, then you just control the zone valve with your BDR91, which in turn controls the UFH pump. Done.

[eightiescalling]

Thanks again for the feedback.

Just to make sure I'm not over simplifying it, on the assumption that the manifold (whatever brand) is supplied with electronic actuators is it as straight forward as buying a single BDR91 and that relay wired to the actuators and pump all in parallel? Or is it one for the pump and one for the actuators?

Then once they're wired in and the YRF87 bound against it making up the zone Evohome works its magic.

Almost feels too easy which makes me think I'm missing something.

[bruce_miranda]

Most manifolds won't come with electric actuators. So it gets simpler. You just wire the BDR91 to open the zone valve feeding the manifold, that in turn switches on the UFH pump. The T87RF becomes the remote temperature sensor.

[rvb99]

Thanks again for the feedback.

Just to make sure I'm not over simplifying it, on the assumption that the manifold (whatever brand) is supplied with electronic actuators is it as straight forward as buying a single BDR91 and that relay wired to the actuators and pump all in parallel? Or is it one for the pump and one for the actuators?

Then once they're wired in and the YRF87 bound against it making up the zone Evohome works its magic.

Almost feels too easy which makes me think I'm missing something.

There are 2 techniques you can use - both only need a single BDR91. In my proposal you wire the ufh circulating pump in parallel with the actuators. When the zone requests heat via the YRF87 temp sensor the BDR will switch open up all 3 connected manifolds actuators and start the ufh pump.

In bruce_miranda's version you keep the manual actuators that come with the ufh manifold (3 to the underfloor pipe circuits are left open, the rest are closed) and you control the feed pipe to the ufh system using a zone control valve such as a HONEYWELL V4043H1080 2 PORT ZONE VALVE 1" BSP 6 WIRE and connect this to the BDR91. Here you have 2 further options. Either connect the ufh circulating pump to the zone valve such that the pump starts when then valve is open and stops when the valve closes OR you can wire the zone valve and circulating pump in parallel. Use of a single zone valve should be cheaper(pick up on ebay) than 3 electric actuators(one for each pipe circuit). Other things you will need of course to consider are wiring distance and piping layout and access.

[eightiescalling]

Thank you both for the time taken to clarify and help me.

So apparently the manifold that they tend to use as standard where more than pipe run is done has electronic actuators and as it's already factored in to the price for the building works I'm not going to worry too much between the two unless there is a practical reason to.

That leaves your approach rvb99 as the favorite - although I like the simplicity of bruce_miranda's zone valve to pump approach.

As this is a new install to a room basically being assembled from ground up with all plumbing and electrics new, wiring and access are simpler - I saw one where the manifold was tucked away in a corner cupboard and a nighmare to get to. Much to my other halfs amusement I tend to insist on being able to get to these things when they're in - planned access never used is always far less painful and destructive! Similarly the pump, manifold and zone valve/BDR will all be in close proximity as a result. Uprated boiler to cater for this and other additional rads has also been done.