Re: Householder here, pls help, downstairs rads cold, enginineer stumped after power
Thank you to everyone that has replied. Take the point that the engineer should know you can't run two pumps .... But he was not the one that fitted new grundfos 15 months ago at a cost of £ 360 ... However, it worked and all rads hot for first time!
Sorry if this is a daft question, I am a woman with very limited knowledge ... Do all boilers have a pump in them? Surely not, otherwise why would you have a pump in airing cupboard which so many people seem to have?
Usually older heat only ones don't have the pump, newer ones does have (especially combis). Extra pump probably was fitted to increase the preassure and push water through the blockage.
It looks like there is a VERY SERIOUS restriction(s) of the flow in the system. The chemicals used before the powerflush had loosened a few clumps of sludge, which had probably blocked the orifice... It may be in/near the pump, gate valves, boiler, its heat exchanger, sludged up droppers, anywhere (but I would suspect the main circuit first, since the boiler is cycling). You need to get yourself a
Good Professional (Like user Bunker or most others on this forum)) or Good Hobby plumber (DIYer who had worked with radiators AND plumbing before, and his family/friends were pleased with his work),
who is ready to spend at least 1-2 FULL DAYS overhauling the WHOLE system. He will need a hand with radiators (very likely), so have one more strong lad available.- Check the flow resistance trough
each system part, flush EACH dropper/radiator
INDIVIDUALLY/DIRECTLY, remove the radiator/gate valves, if there is lack of good flow. Also you'll want someone, who is ready to replace parts of piping, if they are still restricted...
Read/print this: (
http://www.ukplumbersforums.co.uk/c...olution-how-do-proper-cheap-job-yourself.html), to give you some idea of the proper (after)flush, and don't leave the job unattended. If done by pro - the protocol can be varied, but still should be done THROUGHLY. The flusher connection to ONLY RADIATOR won't cut it...
If they have a power flush machine - attach it instead of the Pump, to the boiler, coil (if you've got one) and EACH dropper pair and also each radiator directly, and flush untill clear...
Do fit good magnetic filter to the boiler return at the end (may go instead of the secondary pump, if the boiler has one.
Before taking everything to bits, you can try listening for the water noise, when the pump or flusher is running - it may pinpoint the location of the blockage - noise is similar to half open tap or toilet cistern fill up (esp near the end). If it's sludge blockage, it may not be audible (longer orifice).
