Hello, my Mothers heating failed in the recent UK cold snap. I found the pump was stuck. I have a question about pump orientation. The existing pump flows downwards. The manual for the proposed replacement recommends that it should pump upwards. This would involve rearranging the flow & return pipes which I want to avoid. The existing pump is just after the expansion pipe and it worked for many years pumping downwards. Why is it recommended for Grundfos Alpha to pump upwards? Is the Grundfos really not suitable for this system?
Advice on this and the viability of my proposed 'improvements' below gratefully received.
Thanks.
More info on the system :
It's a vented system with free standing gas boiler at ground level serving 10 rads with TRV's in a large Victorian house (high ceilings) and DHW coil in the cylinder. The pump is level with the boiler, just after the expansion vent pipe and pumps downwards. There is a manual bypass gate valve open 1 turn. There is also a manual gate valve to shut off the heating circuit when DHW only is needed. The system was installed in the early 1970's and regularly serviced by BG, who replaced various parts over the years, including the boiler and pump. The present boiler is a Gloworm Hideaway and the pump is a BG branded Myson Multihead 2. Pump waranty date is 300603, so I presume it has been in service since about the turn of the century. The feed header tank is upstairs, approx 6m above the pump.
I was able to free the pump by turning the spindle by hand and it then ran smoothly. However, the gate valves above and below the vertically mounted pump will not shut off fully and black water sprayed out of the pump spindle nut when loosened. Once I had the pump running there were various grating noises coming from the pipes and I think there must be sludge in the system. Sometimes I could hear the pump struggling. The pump has stuck again on several occasions and felt very hot. Turning by hand was always very stiff, like wadeing through treacle. Then it would just free up and run smoothly.
I am planning to flush the system with Sentinel X400 and replace the pump and valves. Also fit an electric zone valve to the heating circuit so DHW only can be selected on the programmer. Also to fit a vortex eliminator magnetic particle trap in the return pipe. The pump is rated 74W at medium speed so uses a lot of electricity. I am considering a Grundfos Alpha 2 for its better economy. However, this is an expensive pump so will take a while to show a saving. However, I can get a used one with 6 months warranty for similar price to a basic high energy new one and clean out the impeller housing myself. I just think the economics will work out better that way.
Thanks for reading. What do you guys reckon?
Advice on this and the viability of my proposed 'improvements' below gratefully received.
Thanks.
More info on the system :
It's a vented system with free standing gas boiler at ground level serving 10 rads with TRV's in a large Victorian house (high ceilings) and DHW coil in the cylinder. The pump is level with the boiler, just after the expansion vent pipe and pumps downwards. There is a manual bypass gate valve open 1 turn. There is also a manual gate valve to shut off the heating circuit when DHW only is needed. The system was installed in the early 1970's and regularly serviced by BG, who replaced various parts over the years, including the boiler and pump. The present boiler is a Gloworm Hideaway and the pump is a BG branded Myson Multihead 2. Pump waranty date is 300603, so I presume it has been in service since about the turn of the century. The feed header tank is upstairs, approx 6m above the pump.
I was able to free the pump by turning the spindle by hand and it then ran smoothly. However, the gate valves above and below the vertically mounted pump will not shut off fully and black water sprayed out of the pump spindle nut when loosened. Once I had the pump running there were various grating noises coming from the pipes and I think there must be sludge in the system. Sometimes I could hear the pump struggling. The pump has stuck again on several occasions and felt very hot. Turning by hand was always very stiff, like wadeing through treacle. Then it would just free up and run smoothly.
I am planning to flush the system with Sentinel X400 and replace the pump and valves. Also fit an electric zone valve to the heating circuit so DHW only can be selected on the programmer. Also to fit a vortex eliminator magnetic particle trap in the return pipe. The pump is rated 74W at medium speed so uses a lot of electricity. I am considering a Grundfos Alpha 2 for its better economy. However, this is an expensive pump so will take a while to show a saving. However, I can get a used one with 6 months warranty for similar price to a basic high energy new one and clean out the impeller housing myself. I just think the economics will work out better that way.
Thanks for reading. What do you guys reckon?