Underfloor Heating - conflicting advice from installers!

[PhilipKS]

Hi all,

Posted last week on my underfloor installation and asked questions about vented \ pressurised - had another heating engineer round this morning and have had conflicting advice!

The system: Y plan vented, downstairs boiler, upstairs cylinder with adjacent 3 port valve and pump, 8mm micro bore system installed 1986, Worcester 24ri and fast recharge cyclinder installed 2009, 13m2 area of UFH in new conservatory, immediately behing the wall the boiler is fitted on.

Engineer 1: New pump required by boiler, flow for UFH MUST be taken off after pump or new UFH pump and existing pump will conflict. UFH pump and manifold to be installed by boiler. Need to convert from vented to pressurised heating and hot water system, so new expansion vessel & water cylinder required. Convert from Y plan to S plan to allow independent control of UFH; installation of zone valve by boiler to create Y-plan plus won't work. Old microbore likely to be fine operating under pressure.

Engineer 2: location of flow \ return on boiler is ideal, no new pump required. UFH pump and manifold to be installed by boiler. Advisable to convert heating side to pressurised (although may not strictly be required as three storey house and head 9 - 10 meters from heating header tank to UFH install, so likely to be operating near 1 bar downstairs anyway). Leave hot water side gravity fed, no need to change the cylinder. Expansion vessel required for heating if convert to pressurised. Install one new zone valve to allow independent operation of UFH to create 'Y-plan plus' - no advantage converting to full s-plan. Old microbore also likely to be fine operating under pressure.

Both reputable and experience UFH installers, and both quite insistent they are right!

3rd guy coming round Tuesday for last quote....maybe yet another way to do it!!

What I want is a system that works, if it requires a more complex install to achieve that, then so be it!


Any thoughts - cheers
Philip

 

[Agile]

My first thought is that I dont go to properties to give free advice in the guise of giving a quote.

It will have to be a three zone "S" system! I really dont know how he could make such a big mistake unless it was intentional because he sussed that you were only fishing for free advice.

But the main aspect is that I dont agree that UFH is going to be sensible for a conservatory as the heat required from a poorly insulated conservatory is almost certainly more than a UFH system will give.

I expect you have just decided UFH will look neater and consequently you have not considered this and calculated the heat input required. When trying to get free advice from visiting plumbers I am surprised they did not apparently mention heat requirements which should always be the starting point in any design.

Of course perhaps you only want to use it during summer months and only want top up heat in the evenings. In that case UFH will be fine apart from being more expensive than a rad.

You will also want blinds if its to be used after dark otherwise its like being in a goldfish bowl

Did they even mention the two hour warm up time?

Tony Glazier

 

[picasso]

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nothing wrong using a 3 port valve with ufh, the second engineer sounds a bit more savvy than the first

 

[PhilipKS]

Thanks for the thoughts. Realise heat loss will be an issue, hopefully reduced with ultra high spec glass roof etc. It will be a side return so only roof and one end glazed. Installers have suggested UFH may be insufficient on own, hence also considering adding pipework to allow rad installation as well to future proof before plastering.

Agile...re fishing for free advice from plumbers...

"I dont go to properties to give free advice in the guise of giving a quote"

...not sure how getting 3 quotes for what will be an expensive job qualifies as that, and then listening to their suggested approach? One of these guys will get the work. There are clearly a number of ways to tackle this, when you visit a potential customer do you walk round in silence, not answer any questions, and then send a one line quote without an explanation of what you'll do to deliver their requirements?

PS. this is a strange place for someone to hang out that dislikes giving free advice so much I suppose you could always try paypal...