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Discuss Complete central heating system setup - advice please in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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phill bri

Hi there, please help dont have a clue how to set this up. Ive recently installed a complete new central heating system in my house myself. The system is up and running and works okay but I feel it could work alot better if it were setup properly. Im not a plumber and really understand how parts of the system work. I know the radiators need balanced, the circulation pump needs setup properly, as does the automatic bypass valve etc.

However im not sure where or which component to set up first or how they might need re-adjusted as i adjust the rest of the system. So im after some help of how to set things up please.

Details of system:

1930's 2 double bedroom house, 1 medium living room (rad), large kitchen diner (underfloor heating), upstairs large bathroom with towel rad, all rooms with radiators apart from kitchen with UFH. Underfloor heating system connects to central heating circuit like a radiator would, has a blending valve to set temperature, also a grundfos circulation pump. UFH system also has a temperature sensor so pump on comes on when pipe temperature achieved.

The house is due to have a extension with a further 2 bedrooms and games room (if you were thinking boiler maybe a bit big atm.

Worcester greenstar danesmoor utility Regular 18/25 oil boiler. fitted on ground floor (floor standing boiler) open vented regular boiler

Honeywell DU144 automatic bypass valve fitted between flow & return, instructions say to refer to table with boiler min flow requirement & pump curves for pump head, however i cant find this information? how do you work out pump head?

Vented indirect hot water cylinder (not yet heated by boiler, awaiting larger tank before connecting up, pipework currently isolated between mid position valve & tank inc return of course

Worcester magnetic filter fitted just before circulation pump which is just before boiler

Wilo -Yonos PICO 25/1-6 circulation pump fitted to boiler return pipe, between magnetic filter & boiler (always been advised to fit pumps to return pipe by old school plumbers, as pumps last longer due to less heat.) This is one of those differential pressure pumps that can be set to either variable or constant & both at different speeds.

All rads have TRV's & lockshields apart from towel rad in bathroom which just has manual valves.

Honeywell T6r smart thermostsat programmer

Honeywell V4073A MID position valve

Honeywell 10 way connection block

everything wired up and working apart from cylinder stat, will wire this up when cylinder changed out. The Hw system is turned of via programmer.

Rads and system all bled, rads all get nice and hot.

Boiler is on ground floor, magnetic filter and circulation pump next to it, bypass valve & mid position valve in airing cupboard with cylinder, header tanks in loft as vented system, pipework runs in 22mm circuit in ceiling with 15mm outlets & returns to radiators, inc underfloor heating.

I plan on balancing rads with my heat gun, i could also use this to see boiler flow & return temperatures, if thats helpful

Circulation pump wired into boiler, pump comes on with boiler, do I need pump overun?? (boiler manual states nothing on this.)


Current noticable problems:

biggest noticable problems - Boiler seems to be what id say is cycling, boiler doesnt run until the room stat reaches demanded temperature, will demand 21 & boiler will cut out when only 17 or 18c, a few minutes later boiler will re-start itself. The house will eventually reach temperature but shouldnt the boiler run untill temperature is reached? No ofset on stat either.

Now ive wired it exactly how all manuals state and the stat on the boiler itself is set to max. Could this be the boiler stat taking control or is the water in the boiler reached its max temp and stopping boiler? water is then cooling an then boiler comes back on? or is it a flow problem, water not moving through boiler fast enough or moving through rads too quick.

Other problem:

TRV's whine, whinning goes if you move trv, too much pressure from pump? bypass valve incorrectly set? (im overwhelmed as to what to adjust first and how it might effect other things.

UFH seems to have hot spots, is that normal? no cold spots

Sounds like a disaster when I read it back! im sure it just needs a good solid intial setup and then little fine tweeks.

hope you guys can help.

thanks
 

ShaunCorbs

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Ideally you should have the ufh on its own zone ?

You don’t need an auto bypass with a y plan ?

Is the pump wired to the boiler so it can control it ?

Boiler so be set to 65 dc

As for balancing on your rads your looking for a 10dc difference between flow and return

Sounds like maybe cheap trvs ?

Hot spots no who installed it ?
 

SimonG

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What pipe sizing did you do before you started? What size pipework have you fitted and is it plastic or copper.
Do you have a photo of boiler, pump and motorised valves?
 
P

phill bri

Ideally you should have the ufh on its own zone ?

You don’t need an auto bypass with a y plan ?

Is the pump wired to the boiler so it can control it ?

Boiler so be set to 65 dc

As for balancing on your rads your looking for a 10dc difference between flow and return

Sounds like maybe cheap trvs ?

Hot spots no who installed it ?
Hi, boiler instructions said fit bypass, could the motorised valve block all routes if it were to fail? so best to have bypass? I guess i could adjust the bypass so it barely works?

Worcester have today told me the boiler doesnt need pump overun, pump is wired in with boiler so both come on together. also that the stat on the boiler just controls the temp in the heat exchanger not a room stat. worcester suggested the boiler is probably cycling as reaching max temp and may be a flow problem.

they are trvs from screwfix, come with rads cant remember make.

any ideas on how to set up bypass or these wilo pumps? UFH just needs setup really, much more even when run for a decent length of time. thanks
 
P

phill bri

What pipe sizing did you do before you started? What size pipework have you fitted and is it plastic or copper.
Do you have a photo of boiler, pump and motorised valves?
No pics to hand but types and models listed above.

thanks
 
P

phill bri

What pipe sizing did you do before you started? What size pipework have you fitted and is it plastic or copper.
Do you have a photo of boiler, pump and motorised valves?
all 22mm copper & plastic. 15mm outlets to rads from circuit. thansk
 

ShaunCorbs

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No that was for a s plan system y plan always has one open

Drayton are they all on the flow pipes eg the first ones to get hot ?
 
P

phill bri

Hi, Yes all trv on flow pipes, lockvalves on returns, all lockvalves fully ope though as havnt balanced rads yet, thought i better adjust bypass valve and pump speed first.

thanks
 
P

phill bri

Pump on return?
How are open vent and cold feed connected to system?
pump on return before boiler.

Open vent & cold water feed from loft tank are in airing cupboard on boiler flow pipe, 22m vent first then 15mm cold water feed, about 3-4 inches apart, both after bypass valve
 

ShaunCorbs

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Wrong
 

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Ric2013

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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

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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

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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

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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
 
P

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

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

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.
 
P

phill bri

Update: For others peoples reference and a reply thats of useful information, most likely the band wagon with useless answers will reply with some more useless answers for people to read.

ALL DONE and working extremely well.

It was easier to look up how to setup the individual items myself, much easier than getting pointless answers on here that are of no help what so ever!

I asked some very straightforward and basic questions here and got no answers to any questions.

For those that want to know how to do this in the future its simple once researched.

Set your boiler stat up (boiler type & install dependent obviously) so that you flow is around 60c (again dependant on your boiler type & size of system).

Ideally you then want after all setup for your return to be around 20c lower than your flow (not always achievable).

Set your pump up around mid point to start with. Later a good test of your pump speed is to set your pump speed to max, run your system upto temperature, set your pump speed to min, turn of your boiler, wait 20 mins, if your rads are still warm after this then leave your pump speed alone, if they have cooled considerably then turn your pump speed up to the next stage and repeat the process until correct, this doesnt always work depending on what type of pump you have.

Work out which order your radiators heat up in with all valves a trvs open. Set your first rad lockshield about 1/4 open as a intial setup, then adjust the lockshields on your various rads so that you have around 9-12c difference from flow to return pipes. You may have to wait a while between adjustments to let pipework to cool to re-check temps. you may also have to keep rechecking your rad balance when you have adjusted other rads. after rads are all balanced adjust your trvs and flow rad valves to the temp you desire in that particular room.

UFH thats connected like a rad with blending valve, adjust this using the flow and return pipes like you would a radiator, as effectivly thats all it is. you will have to use your UFH pump speed to balance this too.

Auto byoass valve, this is actually simple for this system, wind it all the way closed, use the pressure display on your circulation pump as a guide, slowly open your bypass valve untill you see your pump pressure slightly decrease, this means your bypass is just cracked open, adjust to either close it up a bit or open a little more dependant on what type of system you have. Also all boiler manufactures of heat only boiles recommend using a auto bypass valve regardless of a 's' or 'y' plan system and is also part of your building regs.

Also good to go around your system to check for any air, mine had none and has been running for months.

There will be loads of stupid replies to this but for the non experienced plumber it will be useful information and my system is now balanced very well with all rads getting hot together, no cold spots, even heat from ufh, no boiler overheating or excessive cylcing, spot on!

Addiossss, wont be using this forum again.
 

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