New microbore system - Ch pressure too high?

[Martyng2]

I have just had a new Vaillant Ecomax Pro boiler and vented system installed in my house, 22mm primaries connected to the 10mm microbore that I put in (I just have to hide my pipes!) Whilst everything works fine, when the diverter valve is set to both HW and CH the resistance due to the microbore is such that the water takes the easy route and goes through the HW circuit only. There's not enough flow through the CH. The Grunfos 15 50 pump is set to speed position 3, I've only just noticed this.

This CAN be overcome by programming the HW and Ch to come on at separate times but that seems daft. My installer says I could have a pressure reducing valve on the HW side - is this a good idea, if so what kind/make of valve please? I've had a look on the internet and most seem to be limited to 60 degrees max.

Any alternative ideas please?

Thanks in advance, Martyn

 

[chrishutt]

All you need is a simple valve (gatevalve or ballvalve) that can be partially closed to increase the resistance on the HW circuit, so providing a better distribution of flow.

Forget about Pressure Reducing Valves - they're for a different application entirely. Your installer really ought to know this - is he a proper heating engineer (Corgi reg., IPHE reg., etc)?

 

[Martyng2]

Thanks chrishutt. I meant to say pressure INCREASING valve, obviously! Yes, the installer did say I might need this but I think he's trying to get away with doing the minimum amount of work - and he's so expensive that I don't really want him back.

If I can use a ball valve as you suggest then that's great, I could do that myself. Thanks again.

Martyn

 

[chrishutt]

Avoid the cheapest type of ball valve (costing less than £2 for 22mm) - they can develop leaks at high temps. Might be better to go for gate valve - equally easy to fit. After adjustment remove red hand wheel to deter unauthorised fiddling with adjustment later.

 

[Martyng2]

That's great thank you, I'll give it a try.

Regards, Martyn