recommendation And advice are welcome.

[Old Account]

hi lads,

I just went today to a customer which wants me to convert his back boiler and hot water cylinder to a sealed system. He wants me to install a Vaillant 938 with 11 rads ( most of them are large 1400x600 ) and future 2 bathrooms.
He is worried that the pressure will drop significantly but I assured him due to my experience and based on Vaillant that it won’t happen and that the 938 will be fine. He is upgrading the mains water supply to 32 mdpe.
Will this type of boiler enough for future zoning? He is planning on splitting the zones in to 3 zones which are ufh downstairs, upstairs rads, downstairs rads.

However, at the moment his last radiator in the bathroom upstairs is only working half way ( vertical radiator). The difference between the F&E tank and the vertical Rad is about 10-20cm at max. Is that the problem why it doesn’t work in full?

Thank you for your help

 

[Best]

Should still work.
System dirty, or not balanced, or not piped with big enough pipes, or pump not up to job?

 

[Scott_D]

I would go for an unvented cylinder

 

[Best]

I just realised there are several questions

 

[Old Account]

Should still work.
System dirty, or not balanced, or not piped with big enough pipes, or pump not up to job?

Tha k you very much Gary. To be fair, I believe you are so right about dirty system as it never has been serviced and flushed in the last 50 years. The next thing is the central heating pipes from the boiler are starting in 22mm but after 2 m it reduces to 15mm.at the moment they only have downstairs rads and one added upstairs bathroom. The rest of the property has those old type gas heaters in the wall ( never seen them before ). Surely not balanced either. I was thinking air could be trapped too.

 

[Old Account]

I would go for an unvented cylinder

What’s your experience with storage combi boilers? Have you fitted some before to multiple bathrooms?

 

[Harvest Fields]

Don’t fit the 938 mate. I’m having a mare with one and the hot water at the minute. Boiler and unvented for me

 

[Old Account]

Because the mounted 20-liter storage behind the initial boiler makes as much as a conventional 70-liter storage cylinder therefore I’m thinking it should be well enough

 

[Old Account]

Don’t fit the 938 mate. I’m having a mare with one and the hot water at the minute. Boiler and unvented for me

Really? What problem are you facing mate?

 

[Harvest Fields]

Because the mounted 20-liter storage behind the initial boiler makes as much as a conventional 70-liter storage cylinder therefore I’m thinking it should be well enough

I believe you to be miss informed here mate.