Heating system needs repriming daily


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Old 03-07-14, 02:24 PM
R
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Heating system needs repriming daily

I have a Laars HT330 heat/hot water system that needs to be primed daily. I have reduced the input temp for the heat thinking it was set too high and was boiling over. The bar pressure gague lands at minimum, I prime it to moderate level. It back flushes every few days and the blow out drain fills a 2 gallon bucket in a few days as well. Previously, I had preventive maintenance performed, the chamber is otherwise clean with a thin coating of lime scale. The tech wiped it down with CLR. Is this all I need do to correct.
 
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Old 03-07-14, 03:25 PM
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IF I am correctly interpreting your question you have a problem with either the make-up water pressure reducing valve, a leak in a connected domestic water heater or your expansion tank needs servicing.

More specifically, there is no such thing as "priming" a hot water heating system. If the pressure is falling it indicates that you are losing water. There is no "back flushing" unless this is something you are doing on a manual basis. Nor is there any "blow out drain" that would act without a manual operation.

What I suspect is that the expansion tank has lost its air cushion and THAT is causing the pressure to drop when the boiler cools. With the pressure drop the pressure reducing valve opens to allow more water to enter the system and when the boiler again fires the pressure rises above the safety valve setting and the safety valve discharges lowering the pressure. When the boiler cools the entire cycle starts anew.

Previously, I had preventive maintenance performed, the chamber is otherwise clean with a thin coating of lime scale. The tech wiped it down with CLR. Is this all I need do to correct.
I have no idea of what this "chamber" may be.

Posting several pictures of the installation may help me to help you. I don't need any close up pictures at this time but I do need to be able to see how the various parts are piped together. Pictures MUST be well lit and in focus.
 
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Old 03-08-14, 08:26 PM
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The chamber I was referring to is the firing chamber. Here are images of the setup. Let me know if you need more.


Thanks again for your input

-R
 
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