Valiant Ecotec 637 Low Loss header wiring

I have 10 radiators downstairs and 7 radiators upstairs. My worry about only having the one pump would be that it still wasn't big enough to overcome the resistance of the pipework and I would only know once it had been installed.
Provided the pump is sized for the index radiator when both zones are in operation, there will be no problem. If the zones are running separately there will be a separate index rad for each zone; but when both zones are running the index rad is whichever of the two index rads has the greater head. The flows and losses of the separate zones are not added together. Any combination only occurs in the common pipework, i.e.the 22mm.

This diagram may help:

Sample head drawing.png
 
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Guy's sorry for the late reply on this. My wife went into labour since I last posted and I just haven't had chance to reply.
The guys that were supposed to come and install the new LL header and associated controls has let me down. He said he's not available until the new year now and so I'm left with a baby and a toddler in a house that doesn't get warm.
The past few days have been dreadful, the boiler is constantly showing an egg timer which I have assumed is the S53 fault but this morning when I've checked its showing an 'S07 Heating mode pump overrun', not sure what that means and why it knocks the burner off?
We can't wait for the new year at all for this to be fixed and I don't want to just get someone in that has no idea about LL headers and they come in and make it worse.

One of my friends who's a mechanical consultant had the same problem and he said rather then faffing about like I have, he just installed a new boiler of smilar duty but I assume had a bigger pump, and it worked a treat.
Cost isn't an issue here (within reason), I just need to get some heat in the house sooner rather than later and I feel that I could get someone to install a new boiler quicker than I could find someone to install a LL header and associated controls.
My friends boiler is an ideal logic plus.
 
I've started a new thread on this because it's no longer just about a low loss header.
 
The 637 has a built in pump, but you can add an additional one in series. I had this setup on my system for a while and it "worked" - in that it improved the flow.

I had a 438 boiler, which means the pump was external - so I then took an intermediate step of replacing the pumps with a semi commercial one (the Grundfos 25-80) - and again, this "worked" as well.

However, with 3 zones, each being called at different times and requiring varying flow rates, the LLH solution was the more ideal resolution. I'd persevere and go with that if you have a large house with lots of radiators. If it helps, try looking up commercial installers on Gas Safe register to find someone in your area familiar with LLHs.
 
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The pump in my boiler is a Grundfos 15-75. My preference would be to keep the boier and install a LL header but I just can't find anyone with the knowledge and if they do know then they don't understand the controls side.

I've rang three gas safe installer this morning, one said he had no experience of LL headers and wouldn't feel confident, one sounded like he was drunk and the other said he was too busy.

I don't suppose there' anyone on this forum that's local to Warrington nr Manchester.
 
Also I've just carried out a calculation found on this forum of 6 btu x the cubic footage of the house divided by 3.412 to give the Kw

22000 x 6 =132000/3.412 = 38.7 Kw plus 3kw for hot water.

I've got mine set at 30kw but going off that, my boiler is slightly undersized as well although I know this is a rough estimation.
 
Give Ainsdale Gas a call http://ainsdalegas.co.uk/

Mike is an extremely knowledgeable chap and could be persuaded to come to Warrington if you ask him nicely. Don't try to tell him his job though, let him carry out his own diagnosis and see whether he agrees with the proposed solution...
 
Also I've just carried out a calculation found on this forum of 6 btu x the cubic footage of the house divided by 3.412 to give the Kw
A rule-of-thumb formula like that might have been acceptable when gas was 1 old penny a therm and nobody cared anything about global warming. But in today's climate (pun intended) a proper heat loss calculation is essential. Use the Myson heatloss manager to do a "whole house" calculation" by assuming each floor is a single room (house width x length) heated to an average temperature of, say, 21C. You can do a room by room calculation as well, to check the radiators are correctly sized.
 
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I've tried calling Mike at Ainsdale but got no reply, he's obviously a very busy man.

I've managed to speak to an old colleague (who's Gas safe) he as experience of installing low loss headers on commercial systems but not so much on domestic. However, he's willing to help me installing it and confirm the system is safe once it's installed.

I've spoken with Vaillant this morning who advised that they do a specific low loss header WH40 but it only has one connection on the secondary side, whereas I was hoping for two or three for all zones.

If I was to use this LLH then the supply would go into the primary side of the header and the return before the magnaclean would go into the low loss header, is this correct? Also would I be worth upgrading the size of the pipework here, this at the minute is 22mm flow and return.
From here the secondary side flow would go to the top of my three zone valves and the return from rads/hw back onto the LLH.

Where would the secondary pump go, is it better on the flow or the return and what pump manufacturer would you guys recommend? Grundfos?

After speaking with Vailant, with these boilers theres a connection on the boiler X16 for a secondary pump so I wouldn't have to get a wiring centre, if I only use the one pump.
 
If it helps - I used a Worcester Greenstar LLH, which is good up to 70Kw, and is relatively low priced. I have a Vaillant 438 boiler.

If you use a single secondary pump, it can be wired into the Zone Valve's orange wire so that it comes on only when at least one zone valve is open. The primary pump is wired directly to the boiler to allow for pump overrun.

I've been told the pump should ideally be on the return for any setup - but in particular, if there is a short run from the boiler to the LLH. The magna filter should also be on the return of the primary circuit. The primary pump should be sized to meet the minimum flow rates of your boiler at full power (or whatever you have range rated it to).
 
Hi Fezster, The greenstar LLH has 3 inlet/outlets on the secondary side. If I do decide to go for this, could these just be blanked and then if I ever do need individual pumps for the three zones, the at least the LLH is already installed.
The low loss header would be about 1000-1500mm away from the boiler.
 
Yes, I only used one secondary flow/return for all 3 of my zones. I also only have a single secondary pump.
 

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