Short cycling on start up for the first 30 minutes...

[bruce225]

Was trying to stop the boiler being noisy and found that pump on setting 3 was making the noise so changed it to 2 which cured the noise.

But now since I've done that noticed when the boiler starts up from cold it shorts cycles for the first 30mins or so 10seconds on 10 seconds off but after that seems to run fine full temps on radiator full hot water.

Know I don't know if it used to do this before and I've only noticed beacuse I keep looking at it and checking it, is this the norm??

And if not will it do the CH any harm would prefer to run like this to keep the noise levels dowm

It's a Gloworm express 100 combi sealed system.

Thanks.

 

[45yearsagasman]

Circulation fault, as you were advised on your other post.

 

[bruce225]

Thanks

Just wondered why it clears it's self after a while, wouldn't a circulation fault be constant with radiators not getting there heat?

It could have been doing this for years our timer is set to to be on 30mins before we get in the house, just keeping an eye on it at the moment due to changing pump settings.

Cheers

 

[MrTherm]

@bruce225,

Do you have a 2 x 2 port valve system?

 

[bruce225]

@bruce225,

Do you have a 2 x 2 port valve system?

Sorry I don't know what a 2 x 2 valve is.But looking on Google if its the same as what I'm thinking ie 2 port motor vale, I would say no.

 

[bruce225]

http://www.expert-boiler-repair.co....6ac38ee64e9deb9ef68ac72efeaa27101492f1e-2.jpg

This is not mine but identical.Sorry for the massive picture.

 

[MrTherm]

No, then its as mentioned a circulation problem, can't help any further than suggest maybe to check/re- balance rads with pump speed at 2 setting and not at 3 setting.

 

[bruce225]

Thanks

I've got a cover plan with homeserve just don't like calling them out unless it's broken down rather than just a bit of noise.

 

[bruce225]

Still fiddling probably because of bad weather and can't get out of house.

But my original problem was noise on setting 3 on the pump like rushing water I decided to open all the lock shields to full on both sides of radiator to see if that stopped the rushing noise. I don't have any TRV's

But would that mean that the return flow back to the boiler would be too fast/hot thus that's why the boiler is kicking in and not staying on for very long.

I've switched it back to 3 and it's still short cycling, but tried in on 1 and it still warms the radiators in no time at all which makes me think the circulation problem what was mentioned early might not be my problem.

The CH system is only 8 radiators and what I've read setting 3 would be too high on the pump.

Does balancing help with my problem ie would the return water be cooler after balancing thus making the boiler staying on longer.

 

[ChrisR]

Yes if the first rad on the system is wide open, hot water will go quickly through it back to the boiler and turn the boiler off. You'd have just one very hot rad.
Start with the "quickest" rad(s) only a quarter turn open on the lockshield valve. At about one whole turn it's effectively almost fully open.

 

[bruce225]

So one full turn is complete open thought fully unscrewed would be fully open. I've started at a quarter on the first and by the last fully unscrewed.

Will go and readjust...

Thanks