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    Grumman sunstream control unit (16 Posts)

  • suntortise suntortise @ 9:24 PM
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    Grumman sunstream control unit

    Have an old Grumman Sunstream control unit, previous owner said the heat exchanger was calcified. The solar fluid loop seems very restricted, a garden hose (about 30 - 40 PSI) attached at one end yields a pencil thick stream at the other, about a gallon per minute. Is this normal? The Grundfos UP15 - 42F spins nicely, and the impeller looks good, but i can't get it to pump. There was some black glunk in it and old yellowish antifreeze.

    What should the flow be like, and what can i use to remove the calcification from the domestic hot water loop? I already ran CLR thru that loop for several hours (that pump worked fine). Should the CLR have been sufficient, or should i try a muriatic acid solution for good measure? Or white vinegar?

    Should i do anything to the 332A panels which are copper?

    Thanx for any advice!
  • ChrisNECE ChrisNECE @ 1:00 PM
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    Loop ID

    Are you sure of which loop is which?  I've seen some pretty gunky glycol loops, but usually not enough to restrict flow as you describe.  Maybe you're seeing restricted flow on the calcified domestic side?

    The glycol loop has a check valve (I think lower left corner of the unit) to help with identification.

    Speaking of the check valve, is it possible you're pumping backwards against the check valve and only getting a small amount that's leaking by the check valve?

    Good Luck,
    Chris
  • suntortise suntortise @ 2:21 PM
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    definitely the glycol loop!

    Thanx for replying!

    I used one of the pumping ports , bypassing the check valve, which incidentally passes a little water in the wrong direction. Should i replace the check valve? or is a little reverse leakage acceptable? Tried going in both directions with the hose. Tried tapping on the heat xchgr with a hammer while water flowing thru. Some black particles came out.

    Wondering about the pump, it purrs nicely, impeller looks perfect, can feel air when i operated it briefly out of the system . It pumps little or no water, even when i pumped that loop as full as i could with the garden hose. Is that due to too much resistance in the loop? The Bronze pump in the domestic water loop pumped nicely when i was trying to clean the calcium with CLR.
  • ChrisNECE ChrisNECE @ 10:14 PM
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    Other things to check

    Check valve really shouldn't pass anything in reverse flow. I've gotten in the habit of replacing the check valve and expansion tank anytime I have an old pump station apart. One too many check valves have started clanking after getting the system back together. But you need to figure out your flow problem first.

    Grasping at straws here... I think that unit has fill/drain valves threaded into the pump station. Maybe try your test again, but unthread the drain valve completely from the tapping. Maybe it's the drain valve that's your point of restriction and there's nothing wrong?

    Or remove the pump (I think there are unions) and see if you can snake a coat hanger or piece of copper wire through the heat exchanger.

    By the way, I like your style. When in doubt, hit it with a hammer. ;-)

    Chris
  • mark schofield mark schofield @ 8:54 AM
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    system flush

    I think I have the same system as you. The check valve is between the two boiler drain filler/drain valves. The glycol pump is to the right of the right hand filler/drain valve. When you try to flush/fill the system with the fill hose connected to the right hand valve, does the slow flow come out of the left valve. If so, the clog might be anywhere but the check valve which you have bypassed. When I charge my system pumping into the right hand valve, the flow from the left valve is very fast. There are unions on the left and right end of the glycol hx piping. Worst case you could remove the whole loop and try to isolate the problem, if there isn't crap stuck in the body of the left hand valve. Please post your findings. 
  • suntortise suntortise @ 3:38 PM
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    Have removed the Pump

    Thanx for the suggestion. That is the layout of my system, i.e. check valve btw the drain & fill cocks. I took out the glycol pump, (along with the 2 fill cocks, & check valve & expansion tank) and threaded a pipe into the flange on the right (output side of pump), and the flow coming out of the collector fluid outlet port was still quite anemic. I had found, in addition to the yellowish antifreeze, some black deposits in the pump, & i'm afraid whatever that is, is in the heat xchngr. I'm assuming that heat xchngr is a 1/2" pipe within the 3/4" outside pipe, & i'm wondering how to unclog that. Would CLR or a muriatic acid solution be advised? Or maybe coupling in a pressure washer along with a few choice cuss words!

    From the right hand (output) side of the glycol pump there are no unions, only sweat fittings except for a union that goes to the pressure guage.

    Can't wait to start showering in sunshine!

    ed
  • mark schofield mark schofield @ 5:08 PM
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    backwards flush

    with most of the parts removed, can you try flushing the system "backwards"?
  • suntortise suntortise @ 8:55 PM
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    Backwards flush

    Tried the backwards flush before i removed that stuff, but not since. will give it another try.
  • suntortise suntortise @ 8:15 PM
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    Backwards flush

    Hooked up the hose to the outlet, it had sufficient pressure to fill a 5 galon bucket in 45 seconds.  When hooked up, the water coming out of the righthand glycol pump flange from that same hose after its leisurely trip thru the heat exch. loop took 3 minutes to fill the 5 gallon bucket.

    I would expect some reduction of flow going thru the narrow space between the 1/2 and 3/4 tubes, but it still seems too slow, tho maybe a tad improved over initial observation.

    Wondering if this should be considered good enough, or if i should circulate some CLR, or muriatic acid solution or some other stuff in that loop to loosen things up further.

    Thanx again,

    ed
  • Kevin_in_Denver Kevin_in_Denver @ 2:48 PM
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    airlocked?

    Make sure there isn't any air in the highest part of the sytem. The pump might not be strong enough to force the air back down to the air vent.
    Superinsulated Passive solar house, Buderus in floor backup heat by Mark Eatherton, 3KW grid-tied PV system, various solar thermal experiments
  • suntortise suntortise @ 10:51 PM
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    AIR LOCK

    That could explain why the pump wouldn't pump, as the pump spins nicley, and the impeller seems fine.

    But the last test was with the pump removed, using a garden hose to force water thru the loop.

    Wondering if the results described in my previous post indicate excess clogging, and if muriatic acid or some other agent might be advised to clean any calcium or ancient antifreeze residue from that loop.

    Thanx
  • suntortise suntortise @ 10:51 PM
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    AIR LOCK

    That could explain why the pump wouldn't pump, as the pump spins nicley, and the impeller seems fine.

    But the last test was with the pump removed, using a garden hose to force water thru the loop.

    Wondering if the results described in my previous post indicate excess clogging, and if muriatic acid or some other agent might be advised to clean any calcium or ancient antifreeze residue from that loop.

    Thanx
  • suntortise suntortise @ 10:52 PM
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    AIR LOCK

    That could explain why the pump wouldn't pump, as the pump spins nicley, and the impeller seems fine.

    But the last test was with the pump removed, using a garden hose to force water thru the loop.

    Wondering if the results described in my previous post indicate excess clogging, and if muriatic acid or some other agent might be advised to clean any calcium or ancient antifreeze residue from that loop.

    Thanx
  • gregd gregd @ 8:25 PM
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    Domestic Side Not working

    I installed my unit about 30 years ago and I am running into a problem with the domestic water not circulating. I put in a new grunfos pump (stainless), but the same problem exist. I am not sure how to continue to troubleshoot. Any help would be greatly appreciated
  • gregd gregd @ 8:26 PM
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    Domestic Side Not working

    I installed my unit about 30 years ago and I am running into a problem with the domestic water not circulating. I put in a new grunfos pump (stainless), but the same problem exist. I am not sure how to continue to troubleshoot. Any help would be greatly appreciated
  • gregd gregd @ 8:51 PM
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    Update to domestic side

    I flushed the domestic side through the CF 100 module..... no blockage.
    Putting system together now.
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