boiler advice please

[Glasgow Summer Heat]

Hi Everyone,
This is my first post and would be grateful for any advice. I live in a very old but cold house. Have been living in the house for 17 years and heating has always been an issue. I must have spend in the region of 10K over the past 17 years and still have problem with heating and hot water. I have forgotten how many time the radiators have been balance. I have had the boiler changed twice. Every plumber has blamed the other problem! The problem is that some radiators are hot but others are stone cold and no matter how much "balancing" is done it makes little difference. The cold radiators gradually become warm or even hot after the boiler has been on for a few hours!
I have finally found a problem who appears to be trustworthy. He thinks the problem is that the boiler is too far from the radiators and that's why some of radiators are stone cold and others are piping hot. He also says due to the way the plumbing is the balancing is very difficult. All the pipe work are underneath a very old floor board with difficult access.

He has suggested that I replace the system with 2 Baxi 618 system boilers and also add a Grunfos UPS2 25/80 pump and a 40KW low loss header. He obviously need to install 2 vertical flues. All at a cost of £4200.00

Considering my previous experience, I am naturally suspicious although he seems a nice guys and has done other works for me and quality has been very good.

What do you folks think and specifically what is the advantage of having 2 boilers? He says one would be for heating and the other for hot water but they can also act as a back up if one fails.

I have had a look at the Screwfix and they sell the boilers for 690 each and the pump is about 250. If that is the case is 4200 too steep or it this the going rate for installation and other consumables?

Thank you so much

Sean

 

[ShaunCorbs]

how many rads do you have?
do the furthest rads have the problems or mixture?

also i know you might not like this but if its given you problems all these years i would suggest a re pipe i know its a big upheaval but you will get a system that works

 

[SJB060685]

It sounds like the current boiler pump is just not man enough to supply pressure and flow to farthest parts of the system.
As Shaun says a little more info.
This COULD and im not saying will be sorted with an additional pump and CCT's.

 

[Glasgow Summer Heat]

how many rads do you have?
do the furthest rads have the problems or mixture?

also i know you might not like this but if its given you problems all these years i would suggest a re pipe i know its a big upheaval but you will get a system that works

Hi
We have probabaly 10 radiators and also one room with underfloor heating.
The boiler is outside of the house in the boiler room.
Radiators which are cold not physically are not the furthest from the boiler but j Know that plumbing is all over the place. The plumber did go under the floor board and said the plumbing is old fashioned which makes the balancing difficult but possible. He thought it does not need replumbing.
Why is he using to boiler thought? Is there advantage in using 2 boilers? Surely that's just increasing the cost?

 

[ShaunCorbs]

no advantage in using two boilers in your system prob be worse

turn half your working rads off and do the problem ones heat up?

 

[Glasgow Summer Heat]

no advantage in using two boilers in your system prob be worse

turn half your working rads off and do the problem ones heat up?

The other I switched off the radiator in my sons room and the one in the kitchen which is usually very cold, became nice and hot. 2 of the radiators which are in the old snooker room of the house are permanently switched off. If I turn does ones on the radiators in the bed room go cold. Many plumbers have tried to balance he system but they have given up!

 

[ShaunCorbs]

what pump do you have install currently

 

[Glasgow Summer Heat]

It sounds like the current boiler pump is just not man enough to supply pressure and flow to farthest parts of the system.
As Shaun says a little more info.
This COULD and im not saying will be sorted with an additional pump and CCT's.

What is CCT?
Thank you so much
[automerge]1603577312[/automerge]

what pump do you have install currently

Don't have any pumps...I think there is internal pump in the current boiler

 

[ShaunCorbs]

What is CCT?
Thank you so much
[automerge]1603577312[/automerge]

Don't have any pumps...I think there is internal pump in the current boiler

i would install close coupled tees and try a bigger pump eg ups2 25-80 if that doesnt sort the issue then repipe as its an pipework issue

 

[SJB060685]

What is CCT?
Thank you so much

CCT's is close coupled tee's. Its a means of hydronic separation.
I suspect the internal boiler pump is just not man enough for your system requirements.
Hydronic separation is often used where the primary pump is not enough and allows multiple pumps within the system to function separately without interference of each other.
I'm not saying this is the path to choose, if you're prepared to have the whole system updated then that would benefit you massively BUT more often than not a little thought is all thats needed to overcome such problems.

 

[Glasgow Summer Heat]

i would install close coupled tees and try a bigger pump eg ups2 25-80 if that doesnt sort the issue then repipe as its an pipework issue

What is a closed couple tees?
The current boiler is on its last legs so needs changed anyway.

 

[ShaunCorbs]

What is a closed couple tees?
The current boiler is on its last legs so needs changed anyway.

let’s you fit a bigger pump to the system without effecting the boiler pump

 

[Glasgow Summer Heat]

CCT's is close coupled tee's. Its a means of hydronic separation.
I suspect the internal boiler pump is just not man enough for your system requirements.
Hydronic separation is often used where the primary pump is not enough and allows multiple pumps within the system to function separately without interference of each other.
I'm not saying this is the path to choose, if you're prepared to have the whole system updated then that would benefit you massively BUT more often than not a little thought is all thats needed to overcome such problems.

Thank you so much.
I will ask him about that.
What sort of price should I expect for CCT and pump and one boiler installation?
Is 4200 seems a bit too much?

 

[ShaunCorbs]

Depends on system but a rough guess under 1k for the modification to the cct and pump would try that before you change the boiler unless it’s been turned off for safety reasons

 

[Glasgow Summer Heat]

Depends on system but a rough guess under 1k for the modification to the cct and pump would try that before you change the boiler unless it’s been turned off for safety reasons

That's great. Thank you. The boiler has broken down a few times but still works. It has been ok for the past 6 months.
I will ask him to get the pump and CCT sorted and see how it goes....then decide if the boiler needing changed.
I must admit I have no idea what CCT is! If it is a peice of equipment or sort of system that is purchased.

 

[SJB060685]

As Shaun says CCT's and additional pump is a lot cheaper option, the CCT's is just copper pipe and fittings but the pump is what will be the most and depends on the pump size required.
In my opinion the sign of a good engineer is someone that can fix problems like this without the need to replace everything, which is what a lot of people push for.
As Shaun says I think this is your first approach and if it doesn't work then look into replacing the lot.

 

[Chuck]

Are there TRVs (thermostatic radiator valves) fitted to the existing radiators?

If so, what you are describing seems consistent with having insufficient circulation possibly due to an undersized or failing pump. What I'm thinking is that at start-up, when the system is cold all the TRVs are open. If the pump is weedy, the first radiators in the circuit will bypass the later ones until their TRVs start closing, at which point hot water will start being driven through the later ones.

Blockages or incorrectly sized pipework are also possibilities.

Do you have a 'one pipe' or 'two pipe' system?

IME, it's very rare you need two boilers in domestic premises.

 

[Glasgow Summer Heat]

Are there TRVs (thermostatic radiator valves) fitted to the existing radiators?

If so, what you are describing seems consistent with having insufficient circulation possibly due to an undersized or failing pump. What I'm thinking is that at start-up, when the system is cold all the TRVs are open. If the pump is weedy, the first radiators in the circuit will bypass the later ones until their TRVs start closing, at which point hot water will start being driven through the later ones.

Blockages or incorrectly sized pipework are also possibilities.

Do you have a 'one pipe' or 'two pipe' system?

IME, it's very rare you need two boilers in domestic premises.

We do have TRVs on the radiators. I think he told me it pipe is like a loop and all the radiators come off the loop individually. I am not sure if that what you meant by one or 2 pipe.
My day job is an eye surgeon so plumbing is not my thing!

 

[ShaunCorbs]

Cct is this

two close tees and a bit of pipe

[automerge]1603579343[/automerge]

We do have TRVs on the radiators. I think he told me it pipe is like a loop and all the radiators come off the loop individually. I am not sure if that what you meant by one or 2 pipe.
My day job is an eye surgeon so plumbing is not my thing!

If you have a one pipe system I wouldn’t even bother with it sorry to say repipe

 

[Glasgow Summer Heat]

Cct is this

two close tees and a bit of pipe
View attachment 45909
[automerge]1603579343[/automerge]


View attachment 45910
If you have a one pipe system I wouldn’t even bother with it sorry to say repipe

Looking at this diagram, I think ours is a one pipe system