Valiant 937 ecotec Combi boiler

[D_Hailsham]

Most boilers will modulate down to about a third of their maximum power.

That may sound OK to you but the problem is that a 37 kW boiler typically only goes down to about 12 kW and thats more than most heating systems usually need for 95% of the year.

The boiler then has to on/off modulate which is not so efficient. Its one of the problems of a high powered combi which is specified for DHW output.

I agree with you there. The 937 only goes down to 12kW so if the OP needs 24kW the boiler will stop modulating when the outside temperature is above 10C.

One of the reasons I suggested the Remeha boilers is that they can all (combi, heat and system) modulate down to 6kW, which is equivalent to an outside temp of 15C.

As the OP has picked up, but Tony seems to have forgotten, most decent boilers can be range rated. So a 30kW boiler can be set to a max output of 24kW when appropriate.

 

[Agile]

The max output is not the problem ( unless its grossly over rated and causing short cycling ) as it can modulate down.

Its the minimum power as that causes on/off cycling.

The Remeha does have a big advantage of modulating down nicely but then it also has the disadvantage of not having a merchant based spares backup and most RGIs dont know how to fix them.

I have not forgotten that I was criticised by a problem customer for fitting an "unknown" boiler just because her builder "had never heard of a Viessmann !"

Tony

 

[D_Hailsham]

The Remeha ... has the disadvantage of not having a merchant based spares backup and most RGIs don't know how to fix them.

That's only a problem if the boiler has a reputation for being unreliable.

I like the way they have produced a breakdown parts kit for the installer to carry round, so they always common parts to hand; about the only major components not included are the heat exchangers.

I am not sure if the engineer has to pay for the kit or it is free.

 

[Tipper]

I like the way they have produced a breakdown parts kit for the installer to carry round, so they always common parts to hand; about the only major components not included are the heat exchangers.

I am not sure if the engineer has to pay for the kit or it is free.

That implies that they expect it to breakdown!

Poor design and engineering imho.

 

[D_Hailsham]

That implies that they expect it to breakdown!

You could say that about anything for which the manufacturer supplies spare parts.

Our tumble drier went wrong recently, so we called the engineer out. He came within 2 days and diagnosed the cause as a faulty control panel. He said he would have to order one, which would take a week. He also said that it was a common problem, which I knew as it was the second time this fault had occurred on our machine.

How much better it would have been if he had turned up with the part in his hand and said "I expect it's this, they are always going wrong". That's good customer service.


Why do you think Remeha's are bad design and engineering?

 

[Tipper]

I have no knowledge of those boilers.

My comment was based on the 'expectation' by the manufacturer that it would breakdown. .......................and they will make more in spares over the life of the boiler than they do from selling it in the first place.

 

[Agile]

Our tumble drier went wrong recently, so we called the engineer out. He came within 2 days and diagnosed the cause as a faulty control panel. He said he would have to order one, which would take a week.

He also said that it was a common problem, which I knew as it was the second time this fault had occurred on our machine.

Was that a Remeha or was it a Worcester Bosch?

 

[rizsher]

Guys.. Guys...

Lets focus....

I've given the go ahead (well almost) for a Viessmann 200w along with a Boiler buddy attachment - please tell me its not most stupid way to go..

Apparently this has a small reservoir of h/water that delivers h/water slightly quciker than a regular combi.


Rizwan

 

[Agile]

Its a good boiler if its powerful enough.

And if you had enough mains water flow which your nupty installers dont bother to measure.

And if its installer by an approved person who can give a five year warrantee.

You have been confused! Most boilers have a preheat function for the plate HE which is about 70 cc of hot water. But that is not a "small reservoir" in most peoples dictionary.

I still think you should have a stored system, cheaper, quicker, gives a better flow rate etc. but if you dont and are not happy with your combi then I will be able to say "T told you so...."

Tony

 

[rizsher]

Thought I'd give an update.

Got the Viessmann 200w installed, 35 KW. The work took 3.5 days, thats stripping out the old boiler, h/w cyliner, tanks from the loft. Installing the new boiler and the associated re-piping. Removal of 11 old radiators and re-installation with replacements, plus 2 new radiators which had to be completely re-piped.

System came online last Thursday. Has been wonderful. The house heats up in 20-30 minutes. Hotwater on demand, granted pressure drops a little in multiple demand, but I've run the 2 showers we have simultaneously and it is still perfectly adequate for a shower in both.

Overall, very happy with the system and the installers. If anyone is looking for an plumbing company in the Aberdeen area, I'd be happy to recommend these, just PM me and I'll give the details.

Riz

 

[Agile]

You are lucky because it turned out you had enough mains water flow.

I would never recommend any installer who does not check mains water flow before quoting.

Hopefully they completed the Benchmark Cetificate and will be notifying the installation to Building Control !

Tony

 

[rizsher]

Hi Agile,

Can you please confirm if these two, Benchmark Cetificate and notification of the installation to Building Control are requirements in Scotland as well?.

Regards.
Rizwan

 

[Agile]

The Benchmark Certificate is expected by the boiler manufacturer and any further RGI as evidence that the boiler has actually been commissioned.

As Scotland has its own local regulations I cannot be sure what the Building Control situation is although I would expect it to follow the same arrangement as in England. Some of the many RGIs in Glasgow on here will be able to confirm the situation.

Tony