Boiler for 15mm gas pipe

[xanaxx]

Hi everybody,

I need advice on a non-Combi boiler to run on 15mm gaspipe. The house has a 300 litres megaflo water cylinder with pump, and immersion heater (that can run in emergency without the boiler on), and 16 radiators in the house across two floors. The cooking hob is induction.

The current boiler (Vaillant Ecomax pro 28e) has a leaking heat exchanger after 14 years of use and the gas engineer has capped the gas and recommended an upgrade.

The house had new gaspipes installed 14 years ago, and from I can see, the pipes entering the boiler are 15mm pipes. Gas meter is approximately 7 metres away from the boiler.

Installing 22mm pipes is not an option, hence was looking for recommendations on the boiler replacement in >28 kW range?

Thanks

 

[king of pipes]

Upgrade will be needed in my opinion it's undersized at present your gas Safe registered engineer should guide you . Kop

 

[Deleted member 120897]

It’s not just about stating what existing appliances are installed, it’s about (without giving too much away as gas advice) sizing the installation correctly, you could have 20 elbows fitted for all we know, and there are other factors to consider. Nobody here is on site, not to mention it would be against forum rules and therefore won’t be able to suggest a suitable boiler. Talk this through with a gas safe registered installer.

 

[steadyon]

1. If its 15 mm from the meter, it is under sized for the 28 kW boiler.
2. However, it may only be the last piece of pipe to the boiler which is 15 mm, the rest could be a different size.
3. Unfortunately there is no way of telling what the gas carrying capacity is without inspecting the run from meter to appliance(s).

 

[Enthalpy]

Why >28 kW?

One way to check is to measure the size of each radiator and determine the heat output of each radiator by reference to the maker’s specification or product information for similar radiators.

To the total heat output of the radiators add an allowance for hot water heating, say 3 kW or whatever you like. This gives an indication of the required boiler heat output.

Specifying a boiler with less heat output increases the likelihood that the existing gas pipe will be adequate.

 

[xanaxx]

Thank you all for your comments. That was useful. I agree >28 kW would be unnecessary and I would probably need 26-28kW dependent on the gas supply at the meter. Ill get this checked. Thanks

 

[Timmy D]

If it’s all 15mm, you’re not gonna get bigger than 12kw in there without a pipe upgrade.

 

[gmartine]

The OP has a regular heat only boiler/system don't forget, do get it properly sized though as Enthalpy suggests.