Turbomax 824e vs 828e - Advice Needed

[InterestingThought]

I have a Turbomax 824e. It works great and I don't want to replace it yet.

It is regularly serviced but the pressure in the shower has always been weak the entire time I've had the boiler (20 years). It's a 24kw boiler. When you turn on a tap, hot or cold, the shower slows down to a trickle.

I've noticed that the Turbomax 824e and the 828e are basically identical Combi Boilers, and that all parts are interchangeable (ie PCB, pipes, timer, fan, pump, casing, secondary heat exchange etc all have the same part numbers), except for the chamber burner and the heat exchanger.

Does that mean I could ask my Gas Registered plumber on the next boiler service to change out the Chamber burner and the heat exchanger for the slightly larger 828e versions, and this would mean I would then have a Combi boiler giving out the slightly more 28kw version of hot water?

Do you think he would he agree to do it?

I see no reason why they wouldn't fit as the casing and fittings are identical between the two boilers.

Thanks in advance.

 

[oldbutnotdead]

Before you start doing stuff like that, you need to check your water supply- flow rate and dynamic pressure. If you are only getting 12 l/min at 1 bar (statutory minimum) there's zero to be gained by fiddling with your boiler.
In theory, whoever installed it should have checked the supply was adequate- in practise things change or maybe the installer didn't bother.

 

[InterestingThought]

My cold tap is very powerful. Approx 3 bar pressure from the cold tap.

 

[oldbutnotdead]

OK, good start. How's the flow rate/pressure from the hot tap nearest the boiler?

 

[Deleted member 267285]

The heat exchanger might be a different size, and therefore the cover may not fit?

 

[InterestingThought]

OK, good start. How's the flow rate/pressure from the hot tap nearest the boiler?

About 9 litres per minute.

 

[InterestingThought]

The heat exchanger might be a different size, and therefore the cover may not fit?

I think it is very slightly in thickness. 104 fins to 102 fins.

The cover is identical for both the 824 and 828 as far as I can see. All other parts have the exact same part numbers.

The burner has slightly larger holes in the 828 than the 824.

Do you think my Plumber would say yes or no to fitting the different parts?

Warranty is well and truly over!

 

[InterestingThought]

I had been thinking of installing a new condensing boiler and getting maybe a 35kw one, but the more I've read about condensing boilers, the heaps of issues and repairs everyone seems to have with them.

My house is 2 bedroom, 6 radiators, one shower. So not massive.

I've had this non-condensing Turbomax 824 for 20 years, and apart from replacing the diverter valve twice, the fan once, and a 2p o-ring on the heat exchanger once when it started leaking, I've had zero other issues with it. Cost of repairs in 20 years has maybe totalled £500. So I'd rather keep this one if I can and just upgrade the internals if the Plumber doesn't moan about doing it.

 

[ianmcd]

Do you think my Plumber would say yes or no to fitting the different parts?

simple answer is no

 

[oldbutnotdead]

About 9 litres per minute.

At what sort of pressure? And how many litres per minute do you get from your 3 bar cold tap, and is that static or dynamic pressure?

EDIT Re your plan to swap the innards of your boiler- can't see it happening. A straight boiler swap will be much more cost-effective- you'll get probably a 10 year warranty and no problems with any subsequent maintenance to a Frankenboiler

 

[InterestingThought]

At what sort of pressure? And how many litres per minute do you get from your 3 bar cold tap, and is that static or dynamic pressure?

EDIT Re your plan to swap the innards of your boiler- can't see it happening. A straight boiler swap will be much more cost-effective- you'll get probably a 10 year warranty and no problems with any subsequent maintenance to a Frankenboiler

Actually, I was wrong, I re-tested last night and actually I have.

13L per minute cold tap - approx 3.0 bar pressure
6L per minute from hot tap - don't know the bar

I assume this means my boiler may need a service to get it back to the original 9L a minute which would be a 50% rise in flow rate.

My shower says that 11L per minute is the ideal flow rate for it to work at full pelt. I'm guessing my boiler is below the standard required for it to run at a good pressure.

 

[oldbutnotdead]

Those are very low flow readings. 13l/min at 3 bar dynamic (as in that's the pressure with the tap wide open) implies you have a restricted or blocked cold water supply. The 6l/Min from the hot will be down to headloss from internal pipework and heat exchanger (which makes me think the 3 bar is probably static pressure not dynamic). If it's 'always been like that' the original installer did you no favours, you need to look at your cold water supply. Is it still lead pipe? Are any stoptaps fully open? Is there a rats nest of elbows, bends etc in the supply pipes?

 

[InterestingThought]

Those are very low flow readings. 13l/min at 3 bar dynamic (as in that's the pressure with the tap wide open) implies you have a restricted or blocked cold water supply. The 6l/Min from the hot will be down to headloss from internal pipework and heat exchanger (which makes me think the 3 bar is probably static pressure not dynamic). If it's 'always been like that' the original installer did you no favours, you need to look at your cold water supply. Is it still lead pipe? Are any stoptaps fully open? Is there a rats nest of elbows, bends etc in the supply pipes?

If I get the plumber to replace the heat exchanger for a brand new one, will that increase the flow back again?

I decided instead of using my normal local guy, I found a guy in Dartford that specialises in Vaillant boilers, so I think he'll probably be the best one to deal with this for me. Now, if he'll only just answer his phone so I can get the boiler booked in, that would be awesome!

 

[oldbutnotdead]

13 litres per minute into the house is a marginal flow rate for mains fed hot water. Have you looked at your cold water supply yet? Swapping the boiler at this stage is unwise- you are very unlikely to experience any measurable improvement in your hot water supply without improving the flow rate into the building.