davideliarosenbloom
New Member
A 2011 HTP Elite 150 N is piped in a secondary arrangement off a primary, all running 1.25" copper and is showing a 14 degree Delta T. I believe that the original pump a Grundfos 26/64 and now an old grundfos 14/42 are moving too much water through the HEx especially considering the 1.25" tubing. THe boiler has 1" input/outputs and calls for 10 gpm while both of those pumps are 17 and 22 respectively. However, to add to the mix one of the zones was piped with Entran 2 running at 140 with a high temp cotton 5 micron filter which was changed, however the water shows particles of rubber but is not dark or black, and water treatment has been used because the water is hard here. I am planning on servicing the unit and the HE and expect to find a dirty outside surface, but my question is whether those little black flecks of rubber could be coating the inside of the HE because even using the ISO valves and having throttled down input and outputs one can barely make 20 degrees DElta and I just have a sinking feeling that the heat exchanger is coated inside with hard scale and rubber.
I am considering reverse flushing the HE at hose pressure to see what comes out and maybe adding a cleaner to it and cycling it. ?: Has anyone dealt with HE that have seen Entran 2 for five or six years and what was the experience? I'm going to use a flat plate HE to isolate the problem because its only one zone, but even with the 5 micron filter, wont that plug even more easily given the clearances in the flat plate?
Assuming that the 1.25" copper is providing too much volume for the moment: could someone recommend a grundfos pump (15/10?) that just provides 9 -10 GPM of flow. Otherwise is it acceptable to choke the 14/42 with ball valves regardless of the pump health? What I really need is a VS set up I think but HTP recommends against it and seems to like constant volume pumps with 17 head and 10 gallons per minute which I can;t seem to find. I'm not understanding the relationship of head to time in the HE; because there is very little resistance in the piping its just 2 ft in and two feet out and three total iso valves 1.25".
When I choke enough to get a 25 Delta T the pressure in the boiler rises from 25 to 40 which tells me we're not moving water fast enough don't you agree?
Thanks for your input!
Rosy
I am considering reverse flushing the HE at hose pressure to see what comes out and maybe adding a cleaner to it and cycling it. ?: Has anyone dealt with HE that have seen Entran 2 for five or six years and what was the experience? I'm going to use a flat plate HE to isolate the problem because its only one zone, but even with the 5 micron filter, wont that plug even more easily given the clearances in the flat plate?
Assuming that the 1.25" copper is providing too much volume for the moment: could someone recommend a grundfos pump (15/10?) that just provides 9 -10 GPM of flow. Otherwise is it acceptable to choke the 14/42 with ball valves regardless of the pump health? What I really need is a VS set up I think but HTP recommends against it and seems to like constant volume pumps with 17 head and 10 gallons per minute which I can;t seem to find. I'm not understanding the relationship of head to time in the HE; because there is very little resistance in the piping its just 2 ft in and two feet out and three total iso valves 1.25".
When I choke enough to get a 25 Delta T the pressure in the boiler rises from 25 to 40 which tells me we're not moving water fast enough don't you agree?
Thanks for your input!
Rosy
