Glowworm Swift Flow 80 Fanned Flue Combi Boiler

[glanlay]

I have a Glowworm Swift Flow 80 Fanned Flue Combi Boiler. Recently I have had the Expansion Vessel changed and as water was still coming out of the overflow a new pressure valve and pressure gauge were fitted which cured the overflow problem. However the pressure reading of 1.5 drops to zero in a matter of 2 or 3 hours so that it constantly needs to be topped up.

On the upper floor I cannot see any leaks which I think would quickly become apparent in the ceiling. On the ground floor there are also no visible leaks. The radiators appear to be okay with no air venting required. As long as I have brought the pressure up to 1.5 all radiators get hot and I can get hot water in the bathroom. However the problem persists, with pressure dropping to zero in a matter of a few hours after bring the reading back to 1.5.

 

[Agile]

Have you checked the vent to the pressure release valve?

Sometimes putting a bottle on it overnight will show up that its leaking.

When the EXV was changed what air pressure was it set at before fitting it?

Tony

 

[glanlay]

Have you checked the vent to the pressure release valve?

Sometimes putting a bottle on it overnight will show up that its leaking.

When the EXV was changed what air pressure was it set at before fitting it?

Tony

Many thanks for your reply.

I dont think there is any leak in the vicinity of the boiler as the area around the boiler is as dry as a bone and the boiler now has been topped up several times. When the EXV was changed I dont know what setting was applied. At this stage given the age of the boiler I am thinking of replacing it but I am now concerned I may also be looking at a leak somewhere else in the system. I think more likely at ground floor level where the pipes are hidden.

 

[glanlay]

Is it possible to close down the rad circuit after topping up the boiler by closing the two valves at the flow and return at the boiler? I am not sure if this would eliminate the rad circuit as the possible source of the leakage.

 

[nickso]

dont do that. the valves will leak, they leak too often anyway without being touched.

 

[glanlay]

The minimum pressure for this boiler is 0.7. Is there any maximum pressure when it is refilled that should not be exceeded?

 

[twgas]

Fill system to about 1·5bar, then turn the heating on, as the system heats up does the pressure increase, if so, how much?

 

[glanlay]

Fill system to about 1·5bar, then turn the heating on, as the system heats up does the pressure increase, if so, how much?

As per the above posts I fill it to 1.5 which I thought might be incorrect but in a matter of a few hours the pressure drops to zero. No leaks apparent from the upstairs rads, no overflow activity so currently investigating ground floor piping to see if there is a leak. Some of this pipework difficult to access as it is beneath a laminated floor but no damp apparent.

 

[twgas]

Did the pressure drop without turning the heating on?
A leak un a laminate floor may ot show up, Is the floor concrete or wood?

 

[glanlay]

Did the pressure drop without turning the heating on?
A leak un a laminate floor may ot show up, Is the floor concrete or wood?

Yes the pressure drops over a couple of hours without the heating being switched on. The floor is laminated wood layed over a concrete floor with material between.

 

[twgas]

I would isolate (disconnect) the dowstairs circuit and try again. A leak in the concrete is your most likely problem, it might show up by blowing the laminate, but it might find an escape route downwards and so never show anything.