Two pumps on a heat only boiler quotation

[chloeradhsaw]

I just had a quote for a new boiler install as follows

I dont undertand why a 15-60 boiler pump is needed and a 25-100 pump is needed as well

I currently have an ideal mexico 2 heat only boiler - It has one DAB pump on the boiler return and a 2 port valve at the flow pipe to allow for heating of the hot water cylinder

What am I missing to trust thhis enginner? It a one pipe system with 3 inch steel pipework which is why this one is tricky

To change the boiler, install Vaillant magnetic filter.
✓ Vaillant EcoTEC Plus 438
✓ Vaillant horizontal flue
✓ Vaillant magnetic filter
✓ run new condense pipe to outside
✓ reconfigure pipework for hydronic separation
✓ install new Grundfoss 15-60 pump for boiler
✓ install new Grundfoss 25- 100 pump for heating system
✓ system inhibitor
✓ Registration of the new boiler with Gas Safe
✓ Registration of the boiler with Vaillant
✓ 10-year warranty with Vaillant (annual service required)
TOTAL : £5000 plus VAT
ADDITIONAL:
Should we be able to separate hot water and heating, we will need to add the
following
✓ 2x 28mm Honeywell zone valves
✓ Vaillant wired weather compensation sensor
✓ Vaillant load compensation SensoHOME room thermostat
✓ Vaillant wiring center.
✓ Re wire your heating system for new controls
✓ Registration of the boiler controls with Vaillant
✓ 10 years warranty on the controls
TOTAL: £850 plus VAT

 

[ShaunCorbs]

Condensing boilers don’t really like one pipe systems also won’t run the same as you have will be cooler hence why he’s put on a low loss header and two pumps one for the heating from the header and one for the boiler

Tbh it’s a big expense but I would re pipe and new rads etc

 

[chloeradhsaw]

It seems a shame that a commercial sized heating system (3 inch steel pipework) is going to come out and be replaaced with 22mm plastic for a repipe - Quite apart from the hassle of all floors up

Is there any benefit in keeping a one pipe system which works with a floor standing boiler and useing the wide pipework I have at the moment ?

 

[ShaunCorbs]

It seems a shame that a commercial sized heating system (3 inch steel pipework) is going to come out and be replaaced with 22mm plastic for a repipe - Quite apart from the hassle of all floors up

Is there any benefit in keeping a one pipe system which works with a floor standing boiler and useing the wide pipework I have at the moment ?

Who said plastic 28/22mm copper tube and mlcp (if you have to thread through joists) a lot better than plastic and less crap in the system from the steelside