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View Full Version : New boiler - water pumped backwards through old system



benj
12-31-2009, 10:54 PM
I had a new boiler installed. After the installation, I realized that the new pipes were routed such that the feed was going into the old return lines. I have an 80 year old house with 3" main feed line and 1.5" return. Now the output from the boiler goes into the prior return lines.

I find that I keep getting air in multiple radiaters. I have to bleed some of them every two weeks for 15 minutes before the air is all out. Some just put out a little air and loose pressure. Do I have a clog secondary to displaced deposits related to the water flowing in the opposite direction?

I find that many of the radiaters elevate to the same tempurature regardless if the valve to the radiater is on or off. I suppose that now the valve is on the outlet side of the radiaters instead of the inlet side since the water is routed backwards. Could this be the cause for the valves seemingly not working? Could the radiaters be getting hot water passively through diffusion?
Thanks...

Doherty Plumbing
01-01-2010, 12:57 AM
I had a new boiler installed. After the installation, I realized that the new pipes were routed such that the feed was going into the old return lines. I have an 80 year old house with 3" main feed line and 1.5" return. Now the output from the boiler goes into the prior return lines.

I find that I keep getting air in multiple radiaters. I have to bleed some of them every two weeks for 15 minutes before the air is all out. Some just put out a little air and loose pressure. Do I have a clog secondary to displaced deposits related to the water flowing in the opposite direction?

I find that many of the radiaters elevate to the same tempurature regardless if the valve to the radiater is on or off. I suppose that now the valve is on the outlet side of the radiaters instead of the inlet side since the water is routed backwards. Could this be the cause for the valves seemingly not working? Could the radiaters be getting hot water passively through diffusion?
Thanks...

So you're now pushing into the 1.5" lines and returning on the 3" line?

You're not pushing water through the boiler backwards are you?

You should really repipe the system to how it was before.

benj
01-01-2010, 03:50 PM
Yep, the feed is going into the old return lines...1.5"

Unfortunately the water is going through the boiler the correct way (specified in the boiler manual). If it was going through the boiler and the system backwards, I would be much happier, as I could just reverse the direction of the pumps.

I'm thinking of redoing the piping when the weather warms up. It will be a lot of work.

Doherty Plumbing
01-01-2010, 04:31 PM
Yep, the feed is going into the old return lines...1.5"

Unfortunately the water is going through the boiler the correct way (specified in the boiler manual). If it was going through the boiler and the system backwards, I would be much happier, as I could just reverse the direction of the pumps.

I'm thinking of redoing the piping when the weather warms up. It will be a lot of work.

Just out of curiosity.... How did one manage to pipe the supply and return backwards like that?

benj
01-02-2010, 01:25 AM
The company that installed the boiler realized that that they had the feed and return backwards after it was installed. I worked with them a couple days but on the last few days I had to go to work. They actually never told me about it...my dad, who was here visiting and helping out, told me that several of the installers were talking about it and didn't think it would be a problem. Unfortunately my dad didn't tell me about this until several days after the job was done. At this point, it was a little too late.

johnjh2o1
01-02-2010, 06:00 AM
Get them back to re pipe it. I can't see how anyone that works as a heating contractor could make such a stupid mistake.

John

benj
01-11-2010, 07:09 PM
Don't know if they'll re-pipe it. I wanted to gather some evidence to support my theory that what they did is problematic. Anyone else have some ideas or have experience with this sort of situation. Any feedback would be appreciated.