Danfoss zone valve noisy

[stratplus]

Combi boiler with two zones. Two port for upstairs and another for down.
Zone valve is making a strange noise when heating is turned on or off at the stat (cogs grinding?) Also the rads downstairs (same noisy valve) often don’t come on.
Install is less than two years old.
Anyone else had issues with the Danfoss valve?
Could the problems be overcome by just changing the head?
System probably wasn’t flushed or cleaned when installed.

 

[ShaunCorbs]

bypass valve installed and yes a head change should sort the issue unless the valve body is stiff when you try and do it manually

 

[stratplus]

bypass valve installed and yes a head change should sort the issue unless the valve body is stiff when you try and do it manually

Metal lever seems ok. Valve noisy when first operated but heating intermittent on that zone. New Worcester Erp combi has internal bypass.
Only 18 months old though.

 

[Chuck]

Metal lever seems ok. Valve noisy when first operated but heating intermittent on that zone. New Worcester Erp combi has internal bypass.
Only 18 months old though.

Check the MIs, you may find this warning buried in there somewhere:

"The appliance is equipped with an internal by-pass. The internal bypass is not intended to be a substitute for an external system bypass. An external automatic bypass should be used if the system flow can be significantly adjusted or stopped by zone valves and thermostatic radiator valves (TRV)."

I'm not sure whether this is on all models but I think it's likely.

 

[stratplus]

Check the MIs you are may find this warning buried in there somewhere:

"The appliance is equipped with an internal by-pass. The internal bypass is not intended to be a substitute for an external system bypass. An external automatic bypass should be used if the system flow can be significantly adjusted or stopped by zone valves and thermostatic radiator valves (TRV)."

I'm not sure whether this is on all models but I think it's likely.

Yeah, I have came across that in past.

 

[stratplus]

Yeah, I have came across that in past.

Yeah, I have came across that in past.

Yeah, I have came across that in past.

With pump over run once valve closes could possibly be the noise I heard (valves are above boiler, I would have taken them to an a/c with bypass over ((new build)).
But there are 2 valves and 2 zones and other one is fine which points to the one valve as the problem.