Heating pipe sizes - Plumbing Forum | Plumbers Forums

bbasmdc · 01-09-2008

I had a potton 100 Central Heating boiler feeding 4 large (double) radiators downstairs and 6 large (double) radiators (plus 2 small bathroom rads) upstairs. The flow and return were 28mm splitting into 2x22mm one for upstairs and one for downstairs. My builder is building an extra downstairs room necessitating changes to pipe runs. His plumber has changed the pipework to:
1. Short length of 28mm from boiler reducing to 22mm connecting to upstairs 22mm rad feed circuit.
2. Then a 15mm tee off this 22mm circuit to connect across to the downstairs 22mm circuit.
Any pros out there have any opinions on how performance will be affected by this?
Thanks
Barry

fuzzy · 01-09-2008

any short reduction in pipe will affect the amount of water that will flow through, therefore the amount of heat it can carry will be less, any idea of the output required in each circuit?

bbasmdc · 01-09-2008

Hi Fuzzy

According to an online calculator based on room sizes the requirement for downstairs is 36,000 BTU and Upstairs is 42,000 BTU

Regards
barry

fuzzy · 02-09-2008

im busy at the moment, when i get 5mins ill do the calcs for you

bbasmdc · 03-09-2008

Dear Fuzzy

I found web sites that could do the calcs and concluded that routing both upstairs and downstairs systems through the upstairs pipes is too much for the upstairs pipes to carry. I have instructed my builder to call his plumbers back in and I will confront them with the figures
Thanks for the support
Barry

fuzzy · 20-09-2008

let me know how this goes mate, ive had similar call outs when the prob has been the position of new rads added

bbasmdc · 22-09-2008

Fuzzy
Thanks for your support.
I confronted the plumbers with the figures and they reluctantly told me they had not considered that. I also found that they had connected the combined feed & vent for the DHW primary to the wrong side of the pump.

They said they were not prepared to fix it for nothing so I told them not to come back and have someone else doing the job properly.

I hate having to spend money twice but I just dont trust the first guys.

Regards
Barry

fuzzy · 22-09-2008

was the water pumping up the vent? you say combined, was it an airjeck?

i cannot believe they wont fix their cock up, i agree with you, dont give them any more money, pay somebody else and ask the builder to share the cost

bbasmdc · 29-09-2008

Guys, the builder is as dissapointed in them as I am. I had the option to get insistent on them coming back but decided I just didnt want them back in the house as I had no confidence in them. My hot water cylinder sprung a leak now and I have decided to convert to mains pressure Hot Water so the installation of that will correct their mistakes on the Hot Water. If I had insisted on them returning to fix the CH pipework it would have cost me in delays to the plasterer etc so I decided to take the hit in return for the peace of mind.

Thanks again for all your support. No matter what the outcome it is reassuring to receive your comments .