Dual y plan problem! What would you do?

[Gez2312]

Hi guys , a brief description of what's going on,

Just fitted a new system boiler to replace a floor standing Mexico that's been previously pressurised with a robo expansion kit.

It runs main house heating and dhw cylinder and granny flat heating and dhw cylinder

Its plumbed and wired as two separate y plans each with its own pump.

Problem I'm now having is, and I should have seen this coming a mile away, the mid position valve obviously doesn't close so now boiler has its own pump the valves let heat pass . So..... When any heat is called in granny flat it runs heating in main house and vice versa!

The options I see I have are :

Remove both additional pumps and fit four zone valves , just letting boiler pump do the work.

Add two zone valves before the mid position valve in each system and just wire motor to open i.e from each house pump

Leave house pumps in but remove mid position valve and fit four zone valves

I quite like the idea of the additional pumps, and there is already relays fitted to each system to prevent back feed.

My question is what would you do ?????

Many thanks in advance for your advice

 

[Dan Robinson]

Option one.

 

[Gez2312]

I think I agree!

 

[Agile]

Its obvious to me that what you did would never have worked properly.

The conventional solution would be to fit four two port valves.

But a system like that rather preclude using modern controls like weather compensation.

Tony