vaillant 637 condensing combi boiler

Witch · 10 Jul 2010

Hi I am thinking of getting a vaillant 637 ecotec pro boiler which I know will easily run my 12 rads, but have seen a 'must have' shower with jets etc and need to know if this boiler will supply enough water flow for this sort of water output, I have been told that the pro 28 is not big enough any ideas please

DP · 10 Jul 2010

Not this boiler. This boiler has no facility to give you direct hot water.

Bunnyman · 10 Jul 2010

The 637 is a system boiler designed to work with cylinder etc if u want a Combi u need an 837 or 831 the number 8 designates Combi 6 designates system boiler an the last number ie 31 37 etc is the kw

Witch · 10 Jul 2010

Thanks for the info from both respondents I think you made me realise that it is the flow rate I need to look at for running the shower I want, and the 837 and 937 both have 15.2 so I think this is big enough, Do you agree? Witch

Bunnyman · 10 Jul 2010

Stay awAy from the 937 it has numerous software faults

the 837 is superb hardly any warranty probs

dreadnoughtheating · 10 Jul 2010

Vaillant (and other manufacturers) will quote a flowrate (l/min) at a temp rise of 35 degrees cent.

In the winter months the incoming temp may be as low as 3 degrees. A 35 degree rise at that flowrate would be around blood temp, so not necessarily what you are hoping for.

Also, check that you do actually have a flowrate of at least that required by the shower AND Boiler manufacturer. Or, it will end in tears.

Your GasSafe installer needs to do this first before quoting, if he does not, employ one who does, without being asked to first!

DH

DP · 11 Jul 2010

Why does the installer/ plumber needs to be gas safe if he is fitting a shower. Also, I would have thought the end user would have enough gumption to look at the system spec to establish if boiler can supply quantities of hot water that the shower will put out.

My experience is even the smallest combi gives a far superior shower than an electric 8.5kw unit. But then 8.5kw shower is unlikely to breakdown like a combi will.

Bunnyman · 11 Jul 2010

Blimey DP a touchy plumber??

DP · 11 Jul 2010

Bunnyman, neither touchy nor a plumber, just voicing what i find everyday while repairing and servicing boilers.

By the way a plumber is one who goes way beyond connecting two lengths of pipe. Not many around nowadays me thinks

ianniann · 11 Jul 2010

The heating rate and flow rate from a 37kW combi boiler allows for what most people would call a very good shower. If you are used to a very high flow rate power shower or drencher then you may consider it inadequate. It could also support two simultaneous showers that might best be called adequate, although still better than most electric showers.

The water pressure in most homes and the flow rate provided to a shower by the appropriate pipework will easily support as much water as even a 37kW boiler can heat. Generally you would be aware of low pressure or a poor flow rate if it were bad enough to restrict the shower, but you (or your contractor) should check anyway just to be sure. Ideally test through a shower at the right location. You would need very carefully designed pipework and good mains pressure to support two simultaneous showers or even a shower and somebody else running a tap full on.

Then you confirm the available flow rate and pressure, and how fast the boiler can heat it, against the type of shower you want to fit. Although both the 837 and 937 have the same power, the 937 has a small hot water storage tank that allows a higher flow rate for about the length of a normal shower.

dreadnoughtheating · 11 Jul 2010

DP. as I read the original query, he is looking to change his heating appliance to a Combi - and get a shower that appears to require a good amount of adequately heated water - ergo, he requires the services of an RGI to get it right.

OK, my trade papers (C&G) after the required four years do say 'Advanced Plumbing Craft' and not 'advanced speedfitting', and I am GSR registered too.. so I would like to think that I am reasonably qualified to respond accordingly.

But, 'none taken'

Have a good week.

DH

DP · 12 Jul 2010

Sorry DH, perhaps I am getting grumpy in my old age.

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vaillant 637 condensing combi boiler

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