Dual System: Back Boiler and Oil - rattling

LegacyUser

Hi,

I posted about this before, but the search is disabled so difficult to re-kindle that post.

When I turn on my oil heating there is a noise of rattling/humming, could be pipes type thing in the wall beside the oil timer in the sitting room.
The neighbour next door can hear it - sometimes sounds like there are klingons in the wall. "Shut them up Jim!!".

Had this company out to look at it and they diagnosed that when you turn on the pump for the back boiler (back boiler behind fire which can also heat the radiators), the rumbling wall noise will stop. This guy reckoned that the problem lies in the fact that it is a duel system, but that these duel systems can never work properly together.

He gave me a choice, if I disable the back boiler then the rumbling will stop.
This isn't an option becuase I love my fires .. cosy several times a week. But then the winter comes in I will have fires and also put the heating on timer (for the mornings).

The second choice was to remove valves (something to do with water pushing through them making it rattle) One behind the pump and another out at the boiler house (at a cost of @ 700 euros and possibly taking down part of the wall beside the fireplace - plasterboard).

I'm lost, I don't want to cut off my back boiler, don't want to mess up with valves etc/ I want to be able to turn on the oil heating on timer without having to nip downstairs to turn on the back boiler pump.

Has anyone else had any issues like this? Any advice greatly appreciated.

Bubby

alanc

Not sure if this will help, but worth a try. Lived in a house that worked a dual system. Try turning up the thermostat for the open fire usuall found in the hop press. They had a similar problem and it was because both thermostats were around the same temperature.

AL.

LegacyUser

Hi,
Just checked the hot press. Can't see anything there that could change the temp of the fire. I don't think its that though. Its more on the oil side of things. Got another opinion, rang a boiler expert and he told me to turn down the temperature on the oil burner. It had two dials which were set to 90 each. He recommended changeing them to 65-70. I did this, but noise is still there.


Note: I don't have a fire and oil heating running at the same time. Just oil heating. BUT - if I turn on the pump for the back boiler, the noise in the wall goes away.

JamesM

Certainly you should not have your boiler stats up at 90 - that's almost boiling point. Between 60 and 75 should be OK.
Your noise problem could be a non return valve rattling. But it is also possible that it is the waterpump for the oil boiler. If the bearing is worn, it will rattle and clatter. The switch for the back boiler pump could also shut off the other pump to stop the two pumps working against each other, and that's why the noise stops.
Jim

LegacyUser

JamesM wrote:

Certainly you should not have your boiler stats up at 90 - that's almost boiling point. Between 60 and 75 should be OK.
Your noise problem could be a non return valve rattling. But it is also possible that it is the waterpump for the oil boiler. If the bearing is worn, it will rattle and clatter. The switch for the back boiler pump could also shut off the other pump to stop the two pumps working against each other, and that's why the noise stops.
Jim

Now, that makes sense!! They stats have been that high since I bought the house. Never changed it. I wonder could having the stats that high have damaged the pump.

For definite, your theory of the back boiler pump shutting off the other pump makes sense.
The theory of the non return valve rattling is what the guy who came out today said. He wanted to charge 700 euro to remove that.

Not really sure what to do now. Think I definitely need a second opionion.
Can anyone recommend someone who REALLY knows their stuff?

JamesM

Try turning on your heating. Turn down the boiler stat or somehow switch off the boiler. Make sure that the pump stays on. Now, can you hear the noise ? If so, put your two hands around the body of the pump and see if you can feel a vibration that corresponds to the sounds. You could also put your ear to the pump and see if the sound seems to be coming from it. You can get someone to switch it on and off. You should be able to tell if the sound is coming from it. A pump costs less than Euro200, fitted.
Hope this helps,
Jim.

pipers

bubby wrote:

Hi,
This guy reckoned that the problem lies in the fact that it is a duel system; but that these duel systems can never work properly together. Bubby

A properly designed and installed system (dual, triple, etc) will work correctly.
The position of the non return valve, pump, thermostat, cold feed and expansion pipes are of paramount importance.

bubby wrote:

The second choice was to remove valves (something to do with water pushing through them making it rattle) One behind the pump and another out at the boiler house (at a cost of @ 700 euros and possibly taking down part of the wall beside the fireplace - plasterboard).

If you remove the non return valves you will end up with short circuiting and a major increase in oil consumption as you will heat up the back boiler unnecessarily. This is the equivalent of heating several radiators.

JamesM

pipers wrote:

If you remove the non return valves you will end up with short circuiting and a major increase in oil consumption as you will heat up the back boiler unnecessarily. This is the equivalent of heating several radiators.

And also heating the oil boiler from the Fire - taking hugely from the rads.
Jim.

john joe

im currently building my own house and hot press is 2metres away from solid fuel stove, i have all required pipes allocated in hot press, including oil fired pipework, upstairs and downstairs will be thermostatically controlled using a room stat upstairs and a room stat downstairs, and motorised valves,
Could anyone give me some info on how to link up systems?? eg. location of NRV's and automatic bypass valve in case of motorised valves jamming shut or power failure