Honeywell 2 port zone valve question

[Mister Banks]

I’m investigating an issue where randomly when my CH thermostat stops calling for heat the boiler and pump (it’s a system boiler) turns off and I hear a pipe knocking with a single thud somewhere in the ceiling. This happens whilst the pump is still in overrun and doesn’t happen all the time. My question is, can I manually latch the CH zone valve open without damaging the motor in the valve head. I want to check if it’s the zone valve closing that causes the thud.

Thanks

 

[ianmcd]

yes you can manually latch it, switch the heating off then immediately latch the valve and if the knocking stope likely to be a by pass isseu

 

[Mister Banks]

yes you can manually latch it, switch the heating off then immediately latch the valve and if the knocking stope likely to be a by pass isseu

Thank you. I have an ABV plumbed in just before both the zone valves which appears to operate correctly but I have not been able to determine if it is setup correctly.

 

[Johntheo5]

What is the ABV set to on its index.
Is it a gas or oill boiler with internal or external circ pump, if external post make/mode/setting.

 

[Mister Banks]

What is the ABV set to on its index.
Is it a gas or oill boiler with internal or external circ pump, if external post make/mode/setting.

The ABV is a Honeywell DU145 and is set just a little over 2.5 which I believe is 0.25 bar. The pump is internal to the gas boiler (Worcester Bosch Greenstar 24i system boiler).

 

[Johntheo5]

CAn you post the pump make/model/mode/setting or a close up photo of the pump label and any LEDs that may be on when its running.

 

[Mister Banks]

CAn you post the pump make/model/mode/setting or a close up photo of the pump label and any LEDs that may be on when its running.

Sorry, pump is internal not external, I have edited my post.

 

[ianmcd]

can you post a pic of your zone valves please close and wide shots so we can see your set up

 

[Johntheo5]

Sorry, pump is internal not external, I have edited my post.

It probably isnt the cause of your problem but that setting of 2.6m is way too low IMO and is probably by passing all the time, suggest setting it to 4.0/4.5,
check the arrow direction on both 2 port valves. The arrow on the one on the cylinder coil should be pointing into the cylinder and the one on the rads should be pointing towards the rads.

 

[Mister Banks]

can you post a pic of your zone valves please close and wide shots so we can see your set up

The looped pipe is the flow. The system was vented but is now sealed. The pipe thud started after the new boiler was installed back in 2015 but it was very occassional, I now have a Drayton Wiser system and due to the way it works the thuds are more frequent.

 

[Mister Banks]

It probably isnt the cause of your problem but that setting of 2.6m is way too low IMO and is probably by passing all the time, suggest setting it to 4.0/4.5,
check the arrow direction on both 2 port valves. The arrow on the one on the cylinder coil should be pointing into the cylinder and the one on the rads should be pointing towards the rads.

The zone valves are installed in the correct orientation. The ABV doesn’t operate until the zone valves both close.

 

[ianmcd]

The pipe thud started after the new boiler was installed back in 2015

That could be your problem, it is very common for boiler replacements to mix up the flow anad returns, which now makes the zone valves the wrong way round, still works but will clunk when closing, do you know the model of your old and replacement boilers

 

[Mister Banks]

The flow and return are both correct. The issue is the number of times the Drayton system starts and stops the pump. Last night I jammed open the CH zone valve and didn’t hear a single thud . I will jam the valve open again tonight.

 

[Johntheo5]

Is it only apparent when the CH (Drayton??) zone valve opens?

 

[Mister Banks]

Is it only apparent when the CH (Drayton??) zone valve opens?

Yes, never happens when both valves are open and CH valve closes.