Thermal Store Heating Up Cold Feed Pipe

[John.g]

If you just turn on the CH only, (shut down the boiler), do you still hear/get air problems?

The boiler stat is set to 70C?, what is the TS stat set to?.

Are those Grundfos pumps the old Selectric type?.

 

[iainf3]

If you just turn on the CH only, (shut down the boiler), do you still hear/get air problems?

The boiler stat is set to 70C?, what is the TS stat set to?.

Are those Grundfos pumps the old Selectric type?.

Hi there, the boiler is at 70Deg, the TS thermostat is not connected yet and there is room thermostat controlling the heating set at 20Deg
With the boiler turned off only the single CH pump running, there is little air being sucked in, I would say slightly less than when run with the boiler and boiler pump on as well.
Yes the pumps are the old selectric type.

 

[iainf3]

Hi there, the boiler is at 70Deg, the TS thermostat is not connected yet and there is room thermostat controlling the heating set at 20Deg
With the boiler turned off only the single CH pump running, there is little air being sucked in, I would say slightly less than when run with the boiler and boiler pump on as well.
Yes the pumps are the old selectric type.

Hi there, the boiler is at 70Deg, the TS thermostat is not connected yet and there is room thermostat controlling the heating set at 20Deg
With the boiler turned off only the single CH pump running, there is little air being sucked in, I would say slightly less than when run with the boiler and boiler pump on as well.
Yes the pumps are the old selectric type.

Hi there, the boiler is at 70Deg, the TS thermostat is not connected yet and there is room thermostat controlling the heating set at 20Deg
With the boiler turned off only the single CH pump running, there is little air being sucked in, I would say slightly less than when run with the boiler and boiler pump on as well.
Yes the pumps are the old selectric type.

I must admit that when Ch pumps kicks in you hear air in the system especially going round the flow pipe from the boiler and as mentioned when the pumps stop the cold water in the F&E tank flow righ5 back down to the bottom of the TS. I have attached a image showing the S-bend I put on it yesterday which does seem to help in slowing down the hot water to the F&E tank.

 

[John.g]

Are you getting any air from the rads when/if you bleed them with the CH circ pump off?.
Are you sure there's no other vent somewhere on the CH system?
What are the dimensions roughly of the F&E tank?
What tells the boiler and its circ pump to start and when the burner cuts out does the circ pump keep running?
Does the burner cycle on/ off fairly rapidly?

Edit: I see the F&E tank is 20L capacity.

 

[iainf3]

Are you getting any air from the rads when/if you bleed them with the CH circ pump off?.
Are you sure there's no other vent somewhere on the CH system?
What are the dimensions roughly of the F&E tank?
What tells the boiler and its circ pump to start and when the burner cuts out does the circ pump keep running?
Does the burner cycle on/ off fairly rapidly?

Edit: I see the F&E tank is 20L capacity.

Hello, A wee bit, but did stick that S pipe on the cold feed yesterday as I have just checked it and cleared all will check tomorrow. This is the most the heating has been running have pushed it on all day to see what happens.
The tank is 430 x 300 x 300 high and sits around half full.
The only other vent is the auto air valve on the boiler flow pipe which has been I service for the last 15 years.

On DWH only the boiler and the it’s circ pump start together but once up to temperature eg 70degC the boiler stops and the circ pump continues.

On CH, when selected and the room stat is requesting heat, the boiler and its circuit start up together with the CH pump, but when the room stat reaches temperature it will stop the CH pump as well as both the boiler and its circ pump.

It the unlikely event the boiler gets to temperature first it will be as above and only stop the boiler. This was done to Honeywell heating control drawing, not and S or Y plan, no valves on the system

 

[John.g]

Are you sure that the AAV is working properly on the boiler flow pipe they have a great knack of getting blocked up, I would normally have a isol valve to facilitate cleaning them periodically.

 

[iainf3]

Are you sure that the AAV is working properly on the boiler flow pipe they have a great knack of getting blocked up, I would normally have a isol valve to facilitate cleaning them periodically.

Are you sure that the AAV is working properly on the boiler flow pipe they have a great knack of getting blocked up, I would normally have a isol valve to facilitate cleaning them periodically.

Hello, I don’t know if I am honest I haven’t really had issue before to look at it. It wouldn’t be a proble to take it off and see,
I am looking to drain the system again and change out these opposing tees on the return for the CH circuit. Basically on the main return back to the TS the main bedroom and sitting room are both 15mm returns which come into the 22mm Tees directly opposite main return flow, I am assuming this would cause restriction to the CH system although its been like that for the last 25years

 

[John.g]

If the returd is basically two rads with 15mm returns teeing into the main 22mm return then seems normal?.

 

[iainf3]

Hello, I don’t know if I am honest I haven’t really had issue before to look at it. It wouldn’t be a proble to take it off and see,
I am looking to drain the system again and change out these opposing tees on the return for the CH circuit. Basically on the main return back to the TS the main bedroom and sitting room are both 15mm returns which come into the 22mm Tees directly opposite main return flow, I am assuming this would cause restriction to the CH system although its been like that for the last 25years

Hello, from your last note, I had look at the AAV and found a new one in the garage and have stuck it onto eliminate all threats. Will try it on now and see if that helps any.

 

[John.g]

Very good and just ensure the boiler circ pump is pumping into the boiler return which no doubt you have checked anyway.