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Bunker

Had a call out today to bleed an oil line. While there, I was asked to look at the heating. It's a large house, 22 rads. New boiler. Pipe work is 28mm to and from pump (15 60) up to 22 then 15 to rads. The system has apparently been balanced a few times but never successfully, quite a few rads never get bit unless others are turned off. Is there a bigger dimestic pump I can try , or two in tandem?
Thanks
 
Pipework sizing sounds okay, I'm never sure what the next size up is from a 15-60 tho... Someone will no doubt!
 
i think the next one up is the aplha +, not too sure though :-/
 
I thought an alpha + was just a 15-60 with the energy saving modulation type thing!? It does not look any beefier!
 
Your looking at 180mm pumps next would need to look at Grundfoss website to check the pump curves.
 
s just a 15-60 with the energy saving modulation type thing!? It does not look any beefier!
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I think you may be right, since they have changed to the selectrics now so yeah, I guess it would be just the energy saving module!!
 
22 rads off one pump means a massive single pump in a domestic property, sound a bit shadey, should be lowloss, independant zone pumps blah blah blah.
 
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The magna would probably pay for the extra cost in electricity savings in a year or two.
 
Roger Welton said:
The magna would probably pay for the extra cost in electricity savings in a year or two.
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Do they really save that much electricity? I can't imagine they would save that much! There is quite a difference in cost between the two!
 
Whyme said:
22 rads off one pump means a massive single pump in a domestic property, sound a bit shadey, should be lowloss, independant zone pumps blah blah blah.
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Looking at the pipework, it wouldnt be a huge problem to zone upstairs and down as the CH Flow Ts off up and down after the 2PV - I could either add another valve or maybe throw a 3pv onto the T? WOuld it then be appropriate to install a 15/50 onto each zone leg?
 
Bunker said:
Looking at the pipework, it wouldnt be a huge problem to zone upstairs and down as the CH Flow Ts off up and down after the 2PV - I could either add another valve or maybe throw a 3pv onto the T? WOuld it then be appropriate to install a 15/50 onto each zone leg?
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That would be a good idea. id go for 2 pumps.
 
Bunker said:
Ah, just a thought....wouldnt that be 3 pumps then, one for HW aswell? Please excuse my lack of system design experience..:)
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could you leave the original pump in for the hw ( like a shunt pump) then put a pump on each zone. like you say have 3, belt and braces
 
Whyme said:
could you leave the original pump in for the hw ( like a shunt pump) then put a pump on each zone. like you say have 3, belt and braces
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Id think the original pump would have to be moved to after the HW 2Pv or it would force circulation through the CH 3pv, unless the CH was on 2x2pv. The advantage of a 3pv is you get natural bypass for safety.
 
tbh id go for 2ports over a 3port because of full bore circulation, as far as bypasses go just tee one in were needed.
 
Whyme said:
tbh id go for 2ports over a 3port because of full bore circulation, as far as bypasses go just tee one in were needed.
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That's a good point, so a 3pv is more restrictive? I guess at the least it's a hell of a 90degree turn.
 
Bunker said:
That's a good point, so a 3pv is more restrictive? I guess at the least it's a hell of a 90degree turn.
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yeah they are, in a house with that much demand id plump for 2ports all day long bud. if you think a port and pump for each zone and a pump for the hw rather than just one pump. whats gonna happen if that one great big pump packs up, youve got nothing. if youve got the 3 nicely zoned and one packs up or a valve packs up its not the end of the world..
 
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OK, sounds good, I just hope theres room in his cupboard! Oh, and the wirings gonna be fun...couple of relays me thinks....:)
 
Further to this post, custard called me back to have another look last week, no work had been done on this subject yet. He wanted to revisit the topic but while there he showed me his underfloor heating work so far: one L shape room that used to have 3 rads. He'd laid 3 separate spirals of 15mm Speedfit and was about to plumb each spiral into the closest rad tails. He asked me if pushfit would be ok under the screed.....
I dont know much about underfloor heating but I asked him how how would regulate the heat - he has no intention of doing so, the room is always cold so it would be ideal (!!)
I asked him how he would bleed it "well, the pump would force any air out into the next room radiator I guess"
I told him my opinion, not to mention that unrestricted flow into the returns could trip the boiler stat (?!) and destroy any ability to balance the rest of the system (big house), so the other rads could suffer...
I think I have pretty much decided to 'sack' him as a custard, very nice guy but awful DIYer and doesnt listen.
 
I steer clear of these custards now. The only way they will learn is by making a big mess of it. Sounds like he has.
 
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