Boiler service charge?
- Thread starter Mojo12345
- Start date
Older boilers had open systems and werent pressurised, many modern systems are pressurised and therefore closed systems, so an expansion vessel is needed.
Systems are generally open or closed/sealed and both types have been around since the early days of central heating (we'll ignore the "semi-sealed" weird systems from the 70s..Primatic, Spartans, Hartons etc).
Open systems have a Feed and Expansion cistern at the highest point. The high position creates a static pressure in the system enabling the air to be bled out and to provide a minimum pressure for correct pump/boiler operation etc. The open cistern also allows the system water to expand via the feed pipe by a few percent as the water is heated to maximum temperature. Finally since the system is open the boiler is free to vent steam if necessary during a fault via the safety vent pipe. Some systems have a combined safety vent and feed pipe but the principles are the same.
Closed or sealed system must provide a similar solution. Therefore the expansion vessel (containing compressed air or nitrogen) produces a static pressure and it also allows the water to expand during heating. The safety valve releases excess pressure during fault conditions.
Domestic boilers usually come in 3 flavours (there are plenty of oddballs too)...combi, system and heat only (aka conventional).
Combi and system boilers are normally sealed systems with built in vessels.
Heat only boilers can often be fitted to open or sealed systems...in which case you will have an expansion vessel.
Open systems have a Feed and Expansion cistern at the highest point. The high position creates a static pressure in the system enabling the air to be bled out and to provide a minimum pressure for correct pump/boiler operation etc. The open cistern also allows the system water to expand via the feed pipe by a few percent as the water is heated to maximum temperature. Finally since the system is open the boiler is free to vent steam if necessary during a fault via the safety vent pipe. Some systems have a combined safety vent and feed pipe but the principles are the same.
Closed or sealed system must provide a similar solution. Therefore the expansion vessel (containing compressed air or nitrogen) produces a static pressure and it also allows the water to expand during heating. The safety valve releases excess pressure during fault conditions.
Domestic boilers usually come in 3 flavours (there are plenty of oddballs too)...combi, system and heat only (aka conventional).
Combi and system boilers are normally sealed systems with built in vessels.
Heat only boilers can often be fitted to open or sealed systems...in which case you will have an expansion vessel.
Some of the plumbers I have contacted have said since the boiler was installed in 2009 maybe worth getting a new boiler?,
Therefore it’s been 10 years in use the boiler seems to work ok? Is it worth spending on a new boiler or just getting the current one properly serviced thanks
Therefore it’s been 10 years in use the boiler seems to work ok? Is it worth spending on a new boiler or just getting the current one properly serviced thanks
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Personally I'd just get a full service, new boiler wont be notably different on gas use as this ones already very efficient, so youd just be getting it for the sake of the long warranty which is fine for some folk, but them still needs services at your cost every year to maintain warranty
I'd be far more concerned about the other uninsulated pipework and it's only residual heat loss from the cylinder that's preventing the lot from freezing.
What size is the safety vent pipe running from the top cylinder pipework and up and over the main large cistern...it should be 22mm.
Everything there needs properly lagging..inc. the cistern.
Check where the cistern overflow runs. It looks like the main cistern overflows into the old feed & expansion cistern...but its overflow has been removed.
Overall...it's a rough old setup.
What size is the safety vent pipe running from the top cylinder pipework and up and over the main large cistern...it should be 22mm.
Everything there needs properly lagging..inc. the cistern.
Check where the cistern overflow runs. It looks like the main cistern overflows into the old feed & expansion cistern...but its overflow has been removed.
Overall...it's a rough old setup.
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