Managing UFH Manifold and Mixing Valve

[RichardC]

When something has such WAF that she insists you fit it again, you know it was right...

My wife now simply asks then I start going on about how some bit of tech will be so much better, "What will the WAF be then?"

I am just sorting out quotes at the moment for a 15 zone UFH system, two manifolds. With a couple of loops going in first as it's a renovation, somewhat over the top sensor arrangement to see what method of controlling the room works before rolling it out throughout the house. Using Idratek to control it. Lots of learning to do.

[__CA__]

I've read this thread with interest as I'm currently putting in a completely new central heating system with 3 zones:

1st and 2nd floor radiators (bedrooms and bathrooms)
Ground floor radiators (living rooms and hall)
Ground floor UFH (kitchen)

It will also have an unvented hot water cylinder with a secondary return pump so that you don't have to run the hot taps for ages before they deliver hot water (controlled via a timeclock if not automated).

I only decided to bite the bullet and go with Idratek for lighting in the last couple of weeks, and since then I've been thinking 'why not do the heating as well from the start?'.

Apart from the obvious need for Idratek temperature sensors within each of the 3 zones, I think what I need for the conventional part of the CH and HW system is:

• 2 relays for the CH (radiator) zone valves
• 1 relay for the hot water valve
• 1 relay for the boiler
• Digital input to know whether the hot water cylinder is above/below desired temperature
• 1 relay for the secondary return pump (can be controlled via presence in each of the rooms with a hot water tap)

But when it comes to the UFH I'm not so sure. The spec from Polypipe says there will be a pump, 5 actuators, a 'single zone control pack' and a '4 zone slave pack'. Presumably this means the 5 actuators will all be switched together, so I only need one relay for the pump and another for the actuators?

All advice gratefully received

Thanks

[Viv]

[QUOTE=

But when it comes to the UFH I'm not so sure. The spec from Polypipe says there will be a pump, 5 actuators, a 'single zone control pack' and a '4 zone slave pack'. Presumably this means the 5 actuators will all be switched together, so I only need one relay for the pump and another for the actuators?

You say its just your kitchen that has under floor heating. This means you would only be using one valve on the UFH manifold and the pump. So for these two relays are required.

Viv

[JonS]

I've read this thread with interest as I'm currently putting in a completely new central heating system with 3 zones:

This sounds very familar, the difference in my set-up is no HW recirculation & full UFH on the ground floor. I currently have a conventional set of controls, and intend to add automation to run in parallel so I can switch between the 2 should I need to. The drivers for this are WAF, not freaking out plumbers who are very conservative and will blame new stuff for anything & to aid saleability in (many) years time.
I am planning relays for
each zone valve (2CH 1HW)
each UFH zone
UFH pump
boiler (system boiler so includes pump)
I think the zone valves will be OK with DRB/QRI relays, not sure if the boiler and pump need something with a higher rating.
For the HW cylinder I intend to re-use the standard thermostat, as this wll switch the Zone Valve safely and I am sure I can sense when this has occured -else use the thermostat as a volt-free switch and feed to DI.

On the orginal topic of manifold for mixing - I've got a standard manifold with mixer valve, its all mechanical and works, plumbers understand it, and it means the UFH pipes don't get over heated & perish quickly.

HTH
JonS

[MrFluffy]

On the orginal topic of manifold for mixing - I've got a standard manifold with mixer valve, its all mechanical and works, plumbers understand it, and it means the UFH pipes don't get over heated & perish quickly.

Just a tiny point, and something Ive only just realized recently.
You have to have the pump under control of the system or eventually the water returning from the floor will raise up the "cold" water that the blender mixes in, thus causing the temperature to creep up past what its set to. So when the floor stops demanding heat and turns off the solenoids, the blender doesnt have cold water to blend in and starts to run away thermally.

The light went on when we were looking into a issue with our current install while commisioning it, which unlike the weak solar/electric water heating system at the old house uses a multifuel (wood/oil at the moment) furnace (50Kw hs tarm) which is so overspec'd it can heat the house, the workshops and some outbuildings and still not be at full capacity. Now we've got 90-100deg water circulating in the main loop blended down to 40 for the floor, and the control pack was switching off the actuators for the three zones and it would go into manifold bypass, and a thermostat on the loop bypass circuit would go to 80+ degrees when the blender ran out of cold to blend in. At which point all the circulators were turned off on the ufh circuit...

If you have one of the valves which blocks flow above a certain temperature, then you have a second safety system which stops the above already...

[Paul_B]

Afternoon all,

Resurrecting an old thread as it relates to what I am trying to determine. I have recently replaced an old non-condensing boiler with a wonderful Viessmann model with weather compensation. This was stage 1 of my plan and to some extent I now realise I may have installed a very capable boiler only to stopiing using some of its features in subsequent stages, but on the plus I know if things don't work out I have a good foundation.

Stage two is happening now and this sees the use of a 750L thermal store for providing flexibility in heating our home as future stages see the introduction of solar thermal, solar PV and wood burning stove with back boiler. The store has 100mm of insulation so expected heat loss is 0.5 degrees over 24 hours. I am also moving from a vented to unvented system. My plumber friend is currently going bald trying to make this work and still use as much boiler functionality whilst taking into consideration that solar is not available today only in the future.

Stage three is the distribution side of space heating and DHW. Again plans are afoot to move from radiator based system to UFH, one room has been completed but not commissioned. I'm therefore thinking about a UFH manifold and whilst researching came across the Emmeti M3Vwhich can combine hot and warm water distribution to centrally control radiators and UFH. The manifolds have electro-thermal heads so ideal to control via Idratek. I may also consider the addition of energy monitoring in the form of direct read meters with pulse output (1 pulse = 10l). But before I go and order it I was interested in what others have done and any considerations?

Paul