Boiler is driving me crazy

[Fordy81]

Sorry for another thread.

Long story short, my boiler constantly stops and starts when I request heating and/or hot water. On a couple of occasions it's cut out with an overheating error code. Previously was a solid blockage in the de-aerator.

Today I drained down the system, added X400, refilled the system and turned on heating and hot water. Problem is still happening, but getting the Sentinel through the system.

After leaving for an hour or so and getting roasting hot, I turned the room thermostat (honeywell) down to 16 (current room temp 22) and the little flame went out. However, after doing this I heard the boiler fire up again. Hot water is off, and heating is on rather than being on a timer. I had to turn the heating off at the programmer as I was too hot to see what it would do.

Is this the 3 way port/valve thingy potentially sticking?

I thought the previous problem was a blockage somewhere or the pump not fully functioning.

 

[Armo74]

If it is overheating it is usually down to poor circulation, either sludged up system,scaled heat exchanger pump not working properly.
As all the rads are getting hot and you are getting hot water the circulation can't be all that bad.
Do you have a by-pass valve?
Some boilers require them if you have TRV's even on a Y plan.

 

[Fordy81]

If it is overheating it is usually down to poor circulation, either sludged up system,scaled heat exchanger pump not working properly.
As all the rads are getting hot and you are getting hot water the circulation can't be all that bad.
Do you have a by-pass valve?
Some boilers require them if you have TRV's even on a Y plan.

Well my thought was the pump. But why would the boiler fire up when it's not needed?

I think I do have a bypass valve. Is it the horizontal one?

Untitled

• Fordy81
• 25 Jun 2014
• 4

Untitled

• Fordy81
• 25 Jun 2014
• 3

 

[Armo74]

The horizontal one coming out the bottom of the cylinder is a service valve being used as a balancing valve.
The vertical one after the pump but before the motorised valve looks like a by-pass in 15mm hard to tell from the picture but it looks in the closed position.
Neither are ideal really.

 

[CombustionGuy]

By pass is turned off and service valves are carp as only 8 inside the valve. I would drain and replace both one on the bott of the coil wants to be half open one on the upright pipe wants a automatic bypass valve fitting then see what happens

 

[Fordy81]

The horizontal one coming out the bottom of the cylinder is a service valve being used as a balancing valve.
The vertical one after the pump but before the motorised valve looks like a by-pass in 15mm hard to tell from the picture but it looks in the closed position.
Neither are ideal really.

Hi Armo, yes the vertical one is closed. Always has been. The horizontal one was only half open and I fully opened it, assuming it needed to be.

Would someone be kind enough to link to what the products are that I need?

And are they ok being in the same place as the old ones?

Thanks very much

 

[Fordy81]

By pass is turned off and service valves are carp as only 8 inside the valve. I would drain and replace both one on the bott of the coil wants to be half open one on the upright pipe wants a automatic bypass valve fitting then see what happens

Could that be a potential reason why the kitchen hot tap doesn't have great pressure?

 

[Armo74]

The horizontal one regulates the flow from the boiler through the cylinder coil.
Consult the boiler manufactures instructions about the bypass.
An automatic one in 22mm is the norm available from screwfix don't have the catalogue in front of me so don't know product code but easily found in the catalogue.
Usually you wouldn't need one on a y plan as one port is always open but better to look at manufactures instructions if you have TRV's.

As for the flow issue from the hot water tap could be a few things,
Airlock,insufficient head of water, faulty ballcock in the cold water tank,taps suitable for high pressure instead of gravity, slightly closed service valve, kinked flexi's if they have been used.