I have an open CH/HW system with a gas boiler (one of those 70s/80s things with an ugly gas fire on the front, don’t know the make), HW storage cylinder, Grundfos Selectric 4 pump and Potterton EP2002 control panel. This is the first time I’ve got involved with CH/HW systems and I’m learning fast but, as you’ll see, perhaps making a few mistakes.
Recently I spotted a leak in a 15mm pipe leading to a radiator. I closed off the supply to the expansion tank in the loft and drained off water at the leaky joint (rather than at the drain point). After fixing the joint I opened up the water supply and switched on the HW. The boiler fired up but then shut down after about 3 minutes. 10-15 minutes later the Grundfos started making some ugly noises so I switched off the HW. The cycle repeats if I wait a while, i.e. switch on HW, boiler fires up, boiler shuts down a few minutes later, pump makes progressively more horrible noises.
While checking all aspects of the system I went to the expansion tank and found the lid had virtually disintegrated. On looking inside I saw loads of grot and filth floating on top! Under normal conditions this grot would stay on the surface and not enter the system however, because I drained the tank, I suspect the grot may have reached the pump and/or boiler and blocked the system.
I’d like to open up the pump and check it out but, having been quite an amateur up to now, would appreciate a “beginners guide” to the process. In addition, could the problems be due to air in the system? If so, how do I bleed the HW circulation (I’ve done the radiators)? Anything else I should investigate?
Many thanks.
Online pics of:
Cyclinder and pump, http://www.hooper67.plus.com/CH/cyclinder.jpg.
Close up of pump, http://www.hooper67.plus.com/CH/pump.jpg.
Boiler, http://www.hooper67.plus.com/CH/boiler.jpg.
Recently I spotted a leak in a 15mm pipe leading to a radiator. I closed off the supply to the expansion tank in the loft and drained off water at the leaky joint (rather than at the drain point). After fixing the joint I opened up the water supply and switched on the HW. The boiler fired up but then shut down after about 3 minutes. 10-15 minutes later the Grundfos started making some ugly noises so I switched off the HW. The cycle repeats if I wait a while, i.e. switch on HW, boiler fires up, boiler shuts down a few minutes later, pump makes progressively more horrible noises.
While checking all aspects of the system I went to the expansion tank and found the lid had virtually disintegrated. On looking inside I saw loads of grot and filth floating on top! Under normal conditions this grot would stay on the surface and not enter the system however, because I drained the tank, I suspect the grot may have reached the pump and/or boiler and blocked the system.
I’d like to open up the pump and check it out but, having been quite an amateur up to now, would appreciate a “beginners guide” to the process. In addition, could the problems be due to air in the system? If so, how do I bleed the HW circulation (I’ve done the radiators)? Anything else I should investigate?
Many thanks.
Online pics of:
Cyclinder and pump, http://www.hooper67.plus.com/CH/cyclinder.jpg.
Close up of pump, http://www.hooper67.plus.com/CH/pump.jpg.
Boiler, http://www.hooper67.plus.com/CH/boiler.jpg.