Combi boiler advice! Please help!

[Philipjames74]

I have a 3 storey townhouse and have a Vaillant Ecotech Plus 837 located on the ground floor. The house has 1 bathroom on the middle floor and an ensuite on the top floor. Both have showers.

I'm selling the house and the surveyor has advised the buyers that the boiler isn't man enough.

Have I had the wrong boiler installed? If so what should it have been? The eco-tech plus 837 has up to 28kw and 15.2 litres per min. Is this good? Compared to some of the vailliant boilers, it seems quite a good spec. I'm not sure what's more important, kw or flow rate?!

Any help / advice you can give me would be hugely appreciated!!

Thanks
Phil

 

[Millsy 82]

Ask him for his reasons why it isnt man enough and also ask him for his workings out.

Unless it is a huge house it will cope fine but when dhw is in use in both bathroom and ensuite the pressure will drop on hot water side only.

 

[aggis]

Ask him for his reasons why it isnt man enough and also ask him for his workings out.

Unless it is a huge house it will cope fine but when dhw is in use in both bathroom and ensuite the pressure will drop on hot water side only.

Agree with Milsy 82, are you getting hot water at all sources, is the house warm enough when all radiators on,if so all's well.
If he maintains, asking him to do a full heating loss calculation of your property & calculation of existing radiator sizing....think he'll give it a miss !!!
Combi boilers are fairly slow for filling baths, but 15l/m is very good, it'll work the showers all day long. the only way of improving your water flow is with an unvented cylinder, not a reason for stating the boiler is under rated .

 

[Avatar]

I have heard someone from british gas repeat the same thing - 'oh you can have a combi run more than 1 bathroom'

Rot! - it depends on the flow rate primarily.

If everything works as stated what's the problem? Get a plumber to test all outlets - run the heating and both showers. If fine get him to write an official letter stating there is nothing wrong (as an experts opinion)

I don't think the surveyor can argue with that.

You will be surprised what modern combis can cope with these days, unlike 10 years ago when they could barely fill a bath in an hour!

Some people still believe that combis are still like this alas . . .

 

[GQuigley67]

i have a vaillant 831 and when someone opens the kitchen sink tap downstairs while im in the shower you notice a drop in FLOW RATE but nothing major unlike other combis where the water would just turn cold.

Unless you have 2 showers on at the same time then your 837 will do fine, get your own survey done by a heating professional and tell him to slap the surveyor in the face with it

unlesss....he is talking about the heating requirement being undersized, then that's a different story

 

[AWheating]

Basically your boiler will want to kick out around 10 to 12ltrs per min on the hot water side to get a decent temp. The more hot water fixtures/demand the more flow rate you want. So if you have 12lpm and you open two taps you can only get a total of 12lpm between the two taps. You also need to take diversity into account tho as its unlikely that every hot fixture will be used at the same time. you can try to help matters with flow restrictors at the fixtures.

As suggested ask for the workings out and information how this conclusion was met.

 

[secret squirrel]

I always thought that surveyors have a get out clause,

'gas appliances not checked suggest you get a competent person'

'electricity not checked blah blah'

So, now this one can check out the heating requirements?

Ask for his workings out, may be its the buyers trying to get the cost of a boiler taken off the house value?

 

[AWheating]

just realised its an 837 so you will get more than the 12lpm i first said. I got confused when you said 28kw in the first post 🙁

so yes you will get close to 15lpm. i would think your boiler is suitable just.

 

[GrahamM]

Personally, I believe it will be pushing the boiler on the hot water side with 2 showers and kitchen tap going.
How does your system perform?

 

[stevetheplumber]

id say the surveyor is being paid by your buyers to find faults ask to see his heat loss calcs that alow him to reach that conclusion
find some vailant paperwork which recomends this boiler for your situation you could try e mailing vaillant asking which boilers they recomend describing your situation and layout see what they come back with
peresonally id fit that boiler in your situation

 

[Philipjames74]

Thanks to everyone who's responded to this - your help and advice has helped massively. Very much appreciated.