DS 40 - Thermal Store / Heat Store

[barrycrook]

Yes, the pump does have slot valves. Last plumber changed it by closing these as pointed out by Tony. Pump is about a year or so old as was changed last year. I had multiple calls from homeserve engineers who could not fix our heating issues. May seem not to understand the system we have. Hence this time i've been posting on here, before getting anyone out

I have since not experienced any noise since turning the boiler and pump down.

Last night i turned the boiler back up to HIGH and left the pump on setting 2. 5 am this morning the loud rumbling began again!! Seems to be at end of boiler heating up the store.

So i'm convinced it is something to do with the boiler stat? Is the water getting too hot and the boiler is not cutting out? or some other posts mention the pump cuts out to earlier due to some wiring issue as the boiler stays on for a short while after pump cuts out?

Gut feeling it is over spill from system and escapes via thermal store to F&E tank above, creation the rumbling?

Barry

 

[Andygasman2010]

Correct me if i'm wrong but the replacement pump you had a year ago was the one on the left of the pic? If so this is the heating pump and won't have any baring on boiler/noise issues. The one on the right is the boiler pump (you may already know this)

Off the top of my head i'm not sure if your boiler has a pump overrun facility (this keeps the pump running for a little after demand or when the burner cuts out, this is to dissapate latent heat in the heat exchanger) if your boiler DID have one and it'd failed it could give you the problem you describe.

 

[barrycrook]

Cheers Andy, yes the pump on the bottom left is the one replaced. We also had the other red pump in the below picture replaced. The store thermostat was also replaced around the same time. Since then the store seems to have been ok.

The Boiler feed and return pipes are on the bottom left, the pump is the left one as it is always on when the boiler is lit.

The two pumps on the right Goldstar (Rads) and Grundfos (Conservatory Heater) operate when the heating is on. Flow and return on the for these on the right. Not sure on the blue thing, think this is an automatic valve for the heating.

Also there seems to be a valve above the boiler, does this look like a bleed valve or just a terminator?

I will try and find out about the boiler pump overrun facility. I do know this boiler on the Baxi site was discontinued in 1993. Now the house was built in 1990, so believe it will be the original boiler!

Central Heating Pumps

• barrycrook
• 16 Jul 2010
• 1

Gold Star does the rads, Grundfos does the heater in conservatory

Switch Valve

• barrycrook
• 16 Jul 2010
• 1

Blue thing,i think controls the rad heating

Top of boiler

• barrycrook
• 16 Jul 2010
• 1

Is this a bleed valve?

 

[brig001]

Firstly, I am not a heating engineer, but I have an almost identical setup (Albion Mainsflow and Baxi Solo Boiler) and had the same problem. First thing I checked was the flow temperature from the boiler. This didn't exceed 80 degrees C with the store stat set to 60 and the boiler stat set to maximum, so I guessed that the pump flow was OK as it was taking the heat away from the boiler quickly enough to stop it boiling. I then used 4x Sentinel X400 and left it running for a couple of weeks. After draining and filling a couple of times, I wet vacuumed any remaining sludge from the bottom of the store - immersion heater hole is a good way. A couple more rinses, then filled with 4 x Sentinel X100 and all was quiet. We have since replaced the boiler with a Vaillant Ecotec and kept the store, but that was for efficiency rather than because we had any particular problem.
HTH,
Brian

 

[Andygasman2010]

Hmm in that first pic you posted the pump on the left looks like it should be the heating pump, this is because the upper connection is only half way up the cylinder. If it was the boiler pump the flow/returns should be at the lowest and highest points on the cylinder to give a better spread of heat around it. Maybe it's been piped up wrong but not sure how relevant this would be to your fault.

Which pump is connected to the highest and lowest tappings on the cylinder?

So has your cylinder got 6 direct tappings? a pair for each pump?

I can't think why you'd have a zone valve fitted, where do it's connections go to/from?

 

[barrycrook]

Brian,

Thanks for your post. I think it may be well worth checking the sludge in the bottom of the store, to rule it out. How can i check the flow temperature? Do i just put some gauge on the return pipe?

Also regarding the wet vacuum approach, how do i start getting the immersion heater out? does it unscrew? There seems to be a very large nut around it, bigger than any spanner i have!

Andy,

I have tried to draw a picture for you! Sorry i'm not an artist but will help understand connections / flow and returns. The two pumps (Rads&Conservatory) come off the same feed. Also the auto valve is on the return pipe back from the heating circuit?

Thermal Store Diagram

• barrycrook
• 19 Jul 2010
• 1

 

[Andygasman2010]

Thanks for the diagram, what you have makes sense now! Slightly unconventional but so long as it's working fine... (apart from your noise of course)

Does that zone valve on the heating return open when you have a demand for either rads/conservatory?

 

[barrycrook]

The power to the valve is twinned into the rad pump, so when central heating comes on it must open. Would this be fitted to stop the water moving from the store around the rads?

 

[Andygasman2010]

The power to the valve is twinned into the rad pump, so when central heating comes on it must open. Would this be fitted to stop the water moving from the store around the rads?

Most likely yea