Flush/Fill System or not?

Mplsavant

I've been having some delta T problems, return temp won't hit a high enough mark compared to the supply side on my Buderus GB142/24. I have the pump on speed 1 now after talking to Buderus Tech support. Problem is circulator pump going bad, a clog or bad water is what they think. My heating contractor is coming over again this week to do work on the system. I believe the water was filled originally off main line which was hooked up to salt softener...it's been 5 years, would all that salt being burned off by now, if we flush/fill, clean and add inhibitor, my non-salt water has 12 grains of hardness...buderus says to have 7.....PH of water is 7.5. Going to have the unit super cleaned up and down first and look at circulator pump. Just wondering if flushing/filling should be pursued? Thoughts?

STEVEusaPA

Help me understand your problem

What do you mean by return temp isn't high enough? What's your delta t on this loop? Are you saying you're getting a high delta t? What number are you shooting for? What happens to the delta t when you switch to speed 2 and then 3? What is the pressure? Are you sure all the air is purged? What method was used to determine a bad circ? I don't think that's you problem. I wouldn't flush/fill until the delta t/circ problem is resolved. Although if it's determined you do have to replace the circ, and you don't have isolation valves, your draining anyway.

Mplsavant

More info on problem

The strap on temp shows a return of low 100"s and the supply is 150. The heating side on the control is set to 170 or 190 and never reaches it due to internal controls on the Buderus that limits the heating temp on the unit if if reaches more than a 45 degree delta T. This is happening on the air handler zone and the two wirbo slab zones.



The unit is at full firing capacity but won't get there from what Buderus Tech support said as a delta T problem. On speed 3, the max temp I get is 151, on speed 1, which is what it should be on i get a max of 160. Tech support said it is a water problem, a circ pump problem or a clog.....Does this make sense?