"Stephen" wrote in message
...
Hello,

I spoke over the phone to a plumber to arrange a boiler service. The
plumber tried to sell me a new boiler. Apparently this model is about
20 years old and is relatively inefficient compared to new models. He
tried to sell me a replacement with the argument that the oil saved
will pay for a new boiler in no time, and with the price of oil, he
may have a point!

He said that a new boiler may require changes to the pipework to avoid
an open vent system. He said these were bad because a boiler
malfunction would boil the header tank, which would melt and kill
people. I remember a report in the news about that happening.

What is the alternative to open vent systems. Are open vent systems
really discouraged? How much can I DIY regarding either changing the
pipework or the boiler?

Thanks,
Stephen.


I replaced my oil fired boiler 2 years ago. All DIY. My new boiler does
use less oil.

I kept my plastic header tank. If the boiler generated boiling water I think
that it would be very obvious that something was wrong!
For this to happen both the normal and the emergency cut thermostats on the
boiler would have had to fail, and probably either the H/W or the room
thermostat. I do recall a story in the press but IIRC the problem was
caused by a immersion heater staying on, and the occupants of the house did
ignore some warning signs.

One reason for not having a sealed system is that they are pressurized, and
the wisdom of preasurizing old radiators is debatable.

The main change to the plumbing was a conversion to a fully pumped system.
For this the supply pipe from the header tank now connects to the boiler
return pipe next to the boiler, rather than the loop to the hot water tank
coil.


--
Michael Chare