S plan and Y plan - the do the same thing right?

[mk2phil]

Been reading around the forum as I have what I assume is a C plan system. I've been thinking about chaning it to fully pumped, but both the S plan and Y plan both look like viable options.

To be honest the Y plan looks the best to me as it incorporates it all into 1 valve as opposed to 2. Which is the best system for fully pumped, or perhaps more appropriately when would you choose one over the other?

In my C plan system the zone valve is on the bottom return pipe just as it exits the H cylinder. The CH pump is next to the boiler in the kitchen. Would this set-up favour one configuration over another?

Cheers

 

[ollski]

Yep it would favour an s plan which is a better system in all honesty as it allows you to expand and zone your system in future if required.

 

[Gasguru]

S plan everytime. Easy to wire up and fault diagnose. Most Y plans don't work as intended due to incorrect wiring on installation.

You may require an auto bypass valve with the S plan - check with boiler manual - its good practice anyway especially if there are plenty of TRV's fitted.

 

[Gas2Air]

I'd go for Y plan, no problem really if installed/wired correctly. No need for a 9+ metre bypass either.

 

[Soggy_weetabix]

with olski on this one.

S plan.

Put a bypass in as its very easy to do.

Long term much the better option.

David

 

[namsag]

Both essentially the same but if going say above 8 rads better with an S plan or use a 28mm y plan valve as 22mm will offer more of a restriction

 

[bab]

as you allready have 1 valve on the c plan u can reuse it on the s plan & only have to buy one extra 2port to get the betterset up. your feed & vent may be an issue as to how the systems piped up at the moment as its gravity dhw at the moment , the heatings probably dropping off the boiler with the pump on the return & if thats the case theres a lot off alterations in the pipework to change it to fully pumped, you might have to make it a sealed system as well to get around lack of pipework.

 

[Paul Barker]

If pump is on return beside boiler, feed on return of cylinder vent on flow of cylinder, zone valve before feed pipe on return of cylinder, put other zone valve on return of CH very likely possible near to boiler autobypass on dhw return in airing cupboard between boiler and zone valve.

You should have sufficient wires to airing cupboard if you can get other sone valve near boiler and programmer is near boiler, you have a relatively achievable task depending on your ability.

In future when a valve goes, most likely just need to change synchronous motor. Quite honestly it's worth storing a spare in the airing cupboard because they only ever break down at 8pm on a Saturday. You cannot get the boiler to fire by manually opening a honeywel zone valve as the microswitch doesn't operate, you have to jump the electrical connections if you use manual or make sure hot water is scalding hot to get heating.

Y plan is what all the bodge it and scarpers were fitting before they discovered Combi boilers.

 

[Paul Barker]

Y plan is what all the bodge it and scarpers were fitting before they discovered Combi boilers.

Nah that was unkind of me.

In your circumstance where there are pipeing issues related to safe operation vis a vis feed/expansion and venting s plan may be easier.

In a newly designed system Y plan is OK, many of us believe s plan is of a higher quality. Y plan however has it's proponents. I have Y plan at home, but that's only because I never touch anything at home that isn't broke. I do not worship the god of constant tinkering nor the god of homemakeover programs, it keeps me warm and dry.