New Boiler needs additional pump ?

firesidechat

My sister lives in a two story house with an add on addition.
The boiler is approx 25ft from the house (in garage).
It services 15 radiators.
New boiler was installed this week. GLOW_WORM Flexicom 30 sx.
It is off the mains and a pressurised system.
Once installed it worked perfect for a few hours,"all radiators were nice and hot". That night only 2radiators were working . Plumber came back yesterday and checked the system for air ,which there was none.
They are claiming the original plumbing pipes are too small, I cannot see
that as they are all 3/4 inch. They now want to install an additional pump
upstairs in the house but are giving no guarantee that will solve the problem..They claim they flushed the system before installing the new boiler. Any advice please ?

If it had pipe work issues it wouldn't have got hot the first time, i would want to know what has changed after it ran for the first few hours and it was able to work quite happily, Gary.

firesidechat

Thanks for the reply gary.
No one adjusted anything ,It was working perfect for a while and then lost heat in most of the rads.
Right now only upstairs rads are hot. They want to come in the morning and install a pump upstairs and snake control wires through the walls.
All at aditional expense.

Sorry, i don't mean anything you would have done, if the heat leaving the boiler being pushed by the pump was sufficient to heat the house for a few hours, what has happened that can't now, i would want that questioned answered for the sake of logic, fitting a second pump when the first pump has already proved itself could be hiding a fault of some kind. It would be unfair for me to second guess your installers, but to me if it worked once then something is stopping it from working again and i would want to know why, Gary

slimjimmc

I'm no heating guru but if the ground floor rads are cold and upstairs hot I can't see how the pump is at fault.

If the upstairs rads heat really slowly then the pump may indeed be too weak and convection (hot water rises) allows them to warm up. However if they heat quickly that suggests to me that the pump is capable of lifting a decent flow of hot water up. So, if it can lift water upstairs against gravity it should be able to also push it around the ground floor circuit.
I think the fact that all was fine for the first few hours backs this up, but I'm probably way off.

Do you have zone control valves for upstairs/ground floor, perhaps ground floor one is stuck closed.

Try turning off all upstairs rads and keep the boiler on and check if the ground floor rads heat up? If you're lucky you might just have an air-lock which gets dislodged when you turn off upstairs. Turn them on again and see what happens.