ASHP schematic - Noddy question - CCT

[crispy_wafer]

Just running through my Grant ASHP schematic before I start putting pipes together. Schematic wants a close coupled tee, what does it do?

 

 

[JohnMo]

CCTs provide hydraulic seperation - are you doing a mixed radiator plus UFH system?

[crispy_wafer]

No, I've planned as just UFH, but...  being the chap I am I've run 3 pairs of MLCP pipework for 1st floor rads/fancoils back to the plant room if the need ever arose!

Edited 19 hours ago by crispy_wafer

[crispy_wafer]

So, UFH fed from ASHP, my design flow rates are approx 17l/m.  The internal pump on the Grant can do 20l/m.  I don't mind straying from the schematic.  So, if I remove the pump and mixing valve from the manifold, then pipe straight into the UFH.  In the plant room I'll have the auto bypass and then the two port valve for the UFH zone.  Can I locate a blending valve in the plant room, or does this need to be situated close to the manifold?

 

[Nickfromwales]

11 minutes ago, crispy_wafer said:

Can I locate a blending valve in the plant room, or does this need to be situated close to the manifold?

For what purpose?

[crispy_wafer]

1 minute ago, Nickfromwales said:

For what purpose?

My understanding (please correct me if I'm wrong) to protect the ufh circuit and floor coverings from over temperature should mogwai eat cookies after midnight and turn into a gremlin and takeover the system!  Seriously though, I'm trying to learn, this bit of my Self build is a new topic for me!  I would put it off for a little longer, but I need to get that last bit of wall boarded over so I can the plasterer in to finish the skimming.

[Nickfromwales]

4 minutes ago, crispy_wafer said:

My understanding (please correct me if I'm wrong) to protect the ufh circuit and floor coverings from over temperature should mogwai eat cookies after midnight and turn into a gremlin and takeover the system!  Seriously though, I'm trying to learn, this bit of my Self build is a new topic for me!  I would put it off for a little longer, but I need to get that last bit of wall boarded over so I can the plasterer in to finish the skimming.

You either need a pump to ‘suck’ through a traditional TMV, or to get an ESBE motorised mixer to run off the heat pump.

 

You never see the TMV after a pump, as it needs the recirculating water to function / reference the temp of the water in the loops.

 

If you're having a TMV for Justin, you'll need to leave the manifold as-is. 

[crispy_wafer]

36 minutes ago, Nickfromwales said:

You either need a pump to ‘suck’ through a traditional TMV, or to get an ESBE motorised mixer to run off the heat pump.

 

You never see the TMV after a pump, as it needs the recirculating water to function / reference the temp of the water in the loops.

 

If you're having a TMV for Justin, you'll need to leave the manifold as-is. 

Thankyou, that advice works for me

[JohnMo]

If from heat pump, there is zero need for a mixing valve or additional pump.

 

What Grant heat pump? The R290 has a modulation circulation pump so it will modulate flow rate to match demand - but doesn't do cooling ever, as no option available. R32 will do cooling but not if installed as per Grant instructions.

[crispy_wafer]

Yeah it’s one of the R32 with fixed flow rates, picked up cheap a few years back.  I think the Chofu manual shows the cooling control but tbh I’ve not looked deeply into it, when the place is habitable it may be a point for experimentation.

[JohnMo]

Why do it correctly, as Chofu intended

[marshian]

4 hours ago, crispy_wafer said:

My understanding (please correct me if I'm wrong) to protect the ufh circuit and floor coverings from over temperature should mogwai eat cookies after midnight and turn into a gremlin and takeover the system! 

 

Proper had a laugh at that - thank you

[crispy_wafer]

Yep the cylinder is already prepped ready with the 3 port valve. No worries on that!  My main queries are what to do at the ufh as I need to finalise the pipe work at the manifold.  My manifold and pump set was all supplied and purchased years ago, taking for granted that blending valves and pumps were required.  But I’m sure I’ve read that these were not necessarily required as design and thinking has evolved. - then I started thinking that perhaps the fixed flow pump in the HP may be able to deal with the ufh, reducing complexity and pipe work faff.

[mistake_not]

1 hour ago, crispy_wafer said:

Yep the cylinder is already prepped ready with the 3 port valve. No worries on that!  My main queries are what to do at the ufh as I need to finalise the pipe work at the manifold.  My manifold and pump set was all supplied and purchased years ago, taking for granted that blending valves and pumps were required.  But I’m sure I’ve read that these were not necessarily required as design and thinking has evolved. - then I started thinking that perhaps the fixed flow pump in the HP may be able to deal with the ufh, reducing complexity and pipe work faff.

If you are just doing UFH you should be able to eliminate everything except the 3 port valve to go between the hot water tank / heating (assume you are doing PDHW?)

 

You should have a super efficient system just running the HP flow and return to the UFH (fully open). Obvs if you are paranoid about cookies add a heat diverter (urban plumber had a good vid showing esbe mixer and overheat detector in series) but I wouldn't bother. Only gotcha I can see is making sure you have enough water volume for defrost cycles and ensure you have an expansion tank.

 

(I don't know the cooling set up requirements)