Complete central heating system setup - advice please

[ShaunCorbs]

Wrong

 

[phill bri]

Wrong

very helpful

 

[Ric2013]

Wrong

To go into a full explanation of pump positions relative to the boiler is pointless when anyone can search the forum or web and see the same thing explained at least every month in great detail - to which I'll only add that pump on return did make sense 3000 years ago, but since I have a customer who's 1980's or early 1990's Grundfos is now on the flow of its third boiler, I don't think it's now an advantage compared with the potential pitfalls. Good to mention it though, as otherwise the OP will (may) run into serious problems at some point down the line even though the pump and vent arrangement may not have a direct bearing on the current issues at hand.

Thanks for your contribution to this thread, Shaun. It's a heck of lot of information being asked for and I don't know where to start, personally, though I see you've tried to engage with a number of points. Not sure UKPF existed when I found myself in a similar situation to the OP's. Luckily I had a lot of spare time to do research and scratch my head, which I didn't mind spending since I was saving on the cost of an installer.

To answer one of the OP's questions, I'd be inclined to try a proportional pressure setting and then balance the radiators (some good guides available online or in a decent DIY manual). An infra-red thermometer, used correctly, will be perfectly adequate for this. The practice of using an automatic bypass valve isn't really going to work with a proportional pressure pump, I'm afraid, but needs to be taken out of the equation at balancing stage anyway. Does sound like the pump is on too high a setting.

 

[ShaunCorbs]

Tbh wrong time to ask questions once it’s been installed

Feed and vent are in the wrong position in relation to pump placement hence my diagram/ picture it’s in positive pressure eg pumping over

 

[Ric2013]

Tbh wrong time to ask questions once it’s been installed

Feed and vent are in the wrong position in relation to pump placement hence my diagram/ picture it’s in positive pressure eg pumping over

Exactly. Seems foolhardy to install it first and understand the details after. But each to his own.

Not sure I follow re pump. He's got the pump on the return, and the close coupling is correct IIUC. Surely the risk is negative pressure between the pump and cold feed with increased risk of air ingress (and cavitation at valves?).

 

[ShaunCorbs]

Exactly. Seems foolhardy to install it first and understand the details after. But each to his own.

Not sure I follow re pump. He's got the pump on the return, and the close coupling is correct IIUC. Surely the risk is negative pressure between the pump and cold feed with increased risk of air ingress (and cavitation at valves?).

I understand it as pump is on the return above the boiler and the vent and feed are on the flow in the airing cupboard eg left hand drawing

 

[phill bri]

I understand it as pump is on the return above the boiler and the vent and feed are on the flow in the airing cupboard eg left hand drawing

pump is not above boiler at all

 

[phill bri]

Exactly. Seems foolhardy to install it first and understand the details after. But each to his own.

Not sure I follow re pump. He's got the pump on the return, and the close coupling is correct IIUC. Surely the risk is negative pressure between the pump and cold feed with increased risk of air ingress (and cavitation at valves?).

no, not fool hardy at all, so you dont setup a system after install? not very good practice, there a difference between installing a system and setting it up for best performance! NO air in system hasnt been since install. nothing wrong with pump on return makes no odds.

 

[ShaunCorbs]

Still on the return and feed and expansion is on the flow

 

[phill bri]

Tbh wrong time to ask questions once it’s been installed

Feed and vent are in the wrong position in relation to pump placement hence my diagram/ picture it’s in positive pressure eg pumping over

thats makes no sense atll all, its a simple setup up question and a process that any good plumber undertakes after a install, sounds like you just install it and walk away, not giving your customer a complete service then and getting the best from there system.