Sorry Another Boiler Quote Question

[clayton]

Moved into this house 3 years ago and its always taken about 3 hrs to get the house upto temperature, I found that the pump was connected to the return
pipe so had that changed with a new pump and fitted to the flow side of the system but that has not improve things, not sure if 12 years with the pump on the return has done any damage to the boiler ? The boiler has been serviced.

I've had a quote to remove the very old system water tank ect and convert to a combi system, They want to fit a Glowworm 35Kw boiler with shock arrestor,scale reducer,mag filer and install Hive controls, chemically flush system for £4746.

I can opt for a Vaillant for an extra £395+vat, If the gas supply needs updating thats an additional £580+vat, the house is a 4 bed detached with 14 rads two showers no bath.

Is it worth paying the extra for the Vaillant ?

 

[Phigo]

On the Vaillant website you can get quotes from their approved installers, you may get a better quote.

 

[clayton]

Thanks for the reply Phigo, these are approved Vaillant installers (pro)

 

[Phigo]

Thanks for the reply Phigo, these are approved Vaillant installers (pro)

I'm not saying they aren't, it's just good to get more quotes from the manufacturers approved list. I saved £1100 by getting many quotes.

 

[muggles]

There's no problem with having a pump on the return. Indeed, all new combi & system boilers on the market that I can think of have the pump on the return. The heat-only oil boilers I fit insist on the pump being on the return.

I'd be inclined to start by diagnosing the problems with the existing system before throwing a new boiler at it, which might just suffer the same issues unless you're going for a complete new system.

As for boiler choice, much more information needed but I'd be very wary of any installer who is specifying a Hive, which is one of the worst sheet stats out there. It suggests they don't understand the benefit of modulating controls, and would lead me to ask what else they don't understand. I'd also be wary of an installer who hasn't surveyed the job in sufficient detail to know whether your gas pipe needs upgrading or not. It shouldn't be a case of "if" it needs upgrading, they should already know by calculation whether it does.

Were any flow rate & pressure tests done to determine what your water mains can actually supply, IE whether you can actually run two showers at the same time?

 

[clayton]

Hi yes both flow and pressure tests on the outside garden tap were done, He did look at the gas pipes from the meter but they go into a void under the stairs. I've have a few plumbers look at the system while the BG 330+ runs nice and quiet in the winter I'm sure while getting up to tempreture the boiler shuts off cools down abit then refires.

What heating controls would you recommend I currently have Nest.

 

[muggles]

If you currently have Nest then keep it, Hive would be a significant downgrade. Preferably get a boiler which accepts OpenTherm communication, as that will make the best of what your Nest has to offer.

 

[gas112]

so do your existing rads get v hot within about half hour or do they take hours to get hot to the touch

 

[clayton]

The rads take about an hour to get hot, they never get very hot if the boiler is set to 70 it can take 3 hours to reach this temp.
All the radiators are new, system cleaner added and flushed, the F&E tank cleaned out.

 

[gas112]

The rads take about an hour to get hot, they never get very hot if the boiler is set to 70 it can take 3 hours to reach this temp.
All the radiators are new, system cleaner added and flushed, the F&E tank cleaned out.

sounds very like you system design fault that needs investigating . Could be tee`s in wrong place amongst other faults

 

[clayton]

If going for a Vaillant boiler is my Nest still the best option for controls, I want to be able to turn the heating on from my mobile phone.

 

[muggles]

Better off with sensoCOMFORT

 

[fixitflav]

while getting up to tempreture the boiler shuts off cools down abit then refires.

It's worth sorting out the problem with your existing set-up before spending money on changing. I agree with gas112 that there could be a pipework fault, causing most of the flow to go straight back to the boiler return, only what's left to the rads. Going on/off on the control-stat is a possible symptom.
Also a few more details of your system would be useful. And don't let bidders lead you down the combi route - that's often their default proposal but may not be the best solution.

 

[clayton]

It's worth sorting out the problem with your existing set-up before spending money on changing. I agree with gas112 that there could be a pipework fault, causing most of the flow to go straight back to the boiler return, only what's left to the rads. Going on/off on the control-stat is a possible symptom.
Also a few more details of your system would be useful. And don't let bidders lead you down the combi route - that's often their default proposal but may not be the best solution.

Thanks for your reply.

I moved into this house 3 years ago prior to that it was empty for a year some of the pipework in the airing cuboard was replace due to being partially blocked, The sytem has had a system flush ( not power ) and all the radiators replaced boiler also serviced.

In the past this house was extended so I'm thinking maybe the boiler might be under sized ?
A previous engineer gas rated the boiler to 20kw.

I have two showers and no bath, the stuart turner shower pump that was fitted in 2022 is quite noisey and next to my bedroom this only feeds the first floor shower, the ground floor is gravity fed so is not great, I hoped a combi boiler might improve the ground shower flow plus heat the house faster.

None of the boiler engineers seem that interested in fault finding, one quoted £2600 to run a new hot and cold supply for the ground shower.

Not sure what the correct option is, boiler does eeem to run nice & quiet no issue with heating the water for the tank, its just heating the house during the winter and trying to get better water pressure to the ground shower.

 

[fixitflav]

In the past this house was extended so I'm thinking maybe the boiler might be under sized ?
A previous engineer gas rated the boiler to 20kw.

Unless there's something unusual, 20kW is almost certainly enough if it's working properly. As you probably know, 35kW for a combi is to give acceptable HW flow. But if it is a piping problem it will be the same with a new boiler, combi or regular.
When I moved into my first house, new build, in 1973 there was a problem, long story but there were 2 parallel pipes and hot from the boiler had been tee'd into the wrong one. Symptoms like yours. Builders still on site, I convinced them what the problem was and they fixed it.
Trouble is if you've got something similar it won't be easy to find what's wrong, need to trace the pipe runs.

What you could do is close all the rad iso valves and any bypass valve. If it's piped correctly that would dead-head the pump and boiler, so if you switch heating on you'd hear some nasty noises, get ready to switch off quick if that happens! If it's piped wrongly as I suspect, the boiler won't mind, it will still get flow and go out on the control-stat. That would at least tell you what the problem is, but not where.