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View Full Version : Draining Febco 825 & 850 Procedures


mojob
10-23-2006, 10:50 AM
I ran into a couple of these and was wondering how to properly drain them. According to Febco you have to loosen the covers on the diaphragms and inlet check valves. Is this really needed or are they being overly cautious? Also, if there isn't a blowout fitting on the downstream side of the outlet ballvalve, which test port can you blow through?

Wet_Boots
10-23-2006, 12:25 PM
825's need a complete dismantling and reassembly.

mojob
10-23-2006, 05:17 PM
825's need a complete dismantling and reassembly.
You're pulling my leg, right?

Wet_Boots
10-23-2006, 06:08 PM
Hard to actually stop short of it. You remove the 825Y check valve covers. You remove the relief valve cover, and make sure the relief valve diaphragm pulls away from the body enough to drain all the water out. Also, this is your opportunity to see how the poppets travel in the guides on the covers. If they seem 'sticky' you clean out the guides, and maybe scrape or sand the poppet stems.

If you aren't charging extra for this work, more power to you. Only the most recent designs have no dissassembly requirement. (like a Watts 009) - the older ones could have had extra testcocks for draining out every last bit of water, but they aren't there, for the most part.

This extra work is why I'll always prefer a PVB to an RPZ, even if they cost the same (and they don't)

mojob
10-24-2006, 10:49 AM
Wetboots, thanks for the reply. I guess I need to go back and tell the customer I need to do more work on it. We had a hard freeze before I blew it out so hopefully it didn't break. I also ran into an 850/860 so I guess I'll be going back there to loosen the covers on it. As far as blowing them out, is it better to use the inlet test port or outlet test port?

Wet_Boots
10-24-2006, 11:58 AM
Depending on your air source, you might not be able to blow through a RPZ without the relief valve springing open. That leaves you the outlet testcock only, for winterizing.

Any RPZ with a cover on the side or on the low side in the center, needs that cover loosened or removed to drain part of the relief section. I think the Conbraco line was the only one that might have enough testcocks to eliminate disassembly requirements.

bicmudpuppy
10-24-2006, 09:28 PM
Hard to actually stop short of it. You remove the 825Y check valve covers. You remove the relief valve cover, and make sure the relief valve diaphragm pulls away from the body enough to drain all the water out. Also, this is your opportunity to see how the poppets travel in the guides on the covers. If they seem 'sticky' you clean out the guides, and maybe scrape or sand the poppet stems.

If you aren't charging extra for this work, more power to you. Only the most recent designs have no dissassembly requirement. (like a Watts 009) - the older ones could have had extra testcocks for draining out every last bit of water, but they aren't there, for the most part.

This extra work is why I'll always prefer a PVB to an RPZ, even if they cost the same (and they don't)
I always open 'em up enough to make sure they dump, possibly push some air through with it open to make sure its dry. If you open #4 with air pressure, I find you get the water out of the lower check on the 825s. Then pop the cover. I like to blow through the device but keep the air under 60 psi. Then all I find necessary is to open the cover and let the last water caught in the relief drip. I don't re-assemble at this point. Put it back together in the spring when you can charge the extra to make it pass. Charging extra now puts us out of the market. Making it pass in the spring cuts the LCO guys out who don't do backflow work. Its hard enough to get $75 when a lot of them are charging $50. But most of our customers know that the guy charging less isn't available in the spring :)

Dirty Water
10-24-2006, 09:32 PM
We install Febco 850 DCVA's. Since they are below the frost line, we don't take them apart. I'm wondering if there is still water stuck in the checks valves like a RPZ or does it just stick in the relief valve? I usually open both shutoffs at 45 degree angles and close the main valve.

bicmudpuppy
10-24-2006, 09:53 PM
We install Febco 850 DCVA's. Since they are below the frost line, we don't take them apart. I'm wondering if there is still water stuck in the checks valves like a RPZ or does it just stick in the relief valve? I usually open both shutoffs at 45 degree angles and close the main valve.
I think the title should have been .......860's not 850's. We're talking RPs I *think*. Doesn't matter if your connected before or after the DC, if you blow air through #4, you should suck the water out of the #2 check. I open and drain the BF before connecting air, then blow the system and make sure #4 is clean before shutting the air off. But, then I'm the guy who will cycle zone 4 on and off until that last spray head is dry too. I can still do as many or more per day than anyone I've ever worked with. I just think its worth the extra 30 seconds or two minutes to make sure I've done everything I can to completely void the system.

DanaMac
10-27-2006, 09:26 AM
While we are blowing out an 825y, we will lossen the four bolts and drain out the front. We don't take it all the way off or take out the relief valve. We just get it loose to allow the water out. Then we take out the #2 check valve as this is where it holds water and cracks. Then put back together.

Wet_Boots
10-27-2006, 10:13 AM
I think that would get nearly all the water out, but I'm also checking the device for sticking poppets, so both covers get removed. And sometimes, the relief diaphragm sticks to the cover, so a few more turns of the bolts allow me to just peel it away from the removed cover.

It may be water hardness that determines the schedule of device failure here. The first time I noticed this design flaw was when a customer called about a leak from a 805Y DCVA. Turns out the stuck poppet had pushed against the cover with enough force to actually crack the body casting next to the cover threads. Not a freezing situation, since the device was inside.

justgeorge
10-27-2006, 02:04 PM
Wouldn't it be easier to install the device with a union and simply remove it in the winter and store it indoors?

George

Wet_Boots
10-27-2006, 02:57 PM
And when it gets lost over the winter? Or moved into an unheated garage and freezes? I think the Febco 825/805 is a sort of special case that benefits from closer attention. If RPZs always had enough drains, freeze damage wouldn't be an issue. The Watts 009 seems a step forward, with no need to dismantle anything, as long as you blow out the device (with a low-pressure truck-mount, I can blow the system through the 009 RPZ)

Midlo Snow Maker
10-28-2006, 06:04 PM
i can't believe people take backflows apart for a winterization, unless your blow out is down stream of it. here we blow through them no problems

Dirty Water
10-28-2006, 06:17 PM
i can't believe people take backflows apart for a winterization, unless your blow out is down stream of it. here we blow through them no problems


We do as well, but we run an 8 horse and a 5 horse truck mount compressor in tandem, so we aren't exactly blasting through them.

Midlo Snow Maker
10-28-2006, 06:20 PM
We do as well, but we run an 8 horse and a 5 horse truck mount compressor in tandem, so we aren't exactly blasting through them.
i gotcha we cary 125 - 185 cfm behind the trucks blow dry them suckers:laugh:

Wet_Boots
10-28-2006, 06:41 PM
i can't believe people take backflows apart for a winterization, unless your blow out is down stream of it. here we blow through them no problemsYou might easily grab enough water with a high-cfm blast through an RPZ. Or not. Of course, high air heat, or rattling plastic innards, might make the manufacturer caution against this practice a case in point. I think the only Y-pattern RPZ that could be sure of not leaving behind a damaging amount of water on a lower-cfm winterizing might be Conbraco's. Their checks are both oriented upwards, and there's an extra testcock on the relief valve cover, so that part could get drained/blown without getting the wrenches out.

Midlo Snow Maker
10-28-2006, 06:46 PM
You might easily grab enough water with a high-cfm blast through an RPZ. Or not. Of course, high air heat, or rattling plastic innards, might make the manufacturer caution against this practice a case in point. I think the only Y-pattern RPZ that could be sure of not leaving behind a damaging amount of water on a lower-cfm winterizing might be Conbraco's. Their checks are both oriented upwards, and there's an extra testcock on the relief valve cover, so that part could get drained/blown without getting the wrenches out.
never been an issue, think god we don't see many conbreako's around here anymore

Wet_Boots
10-28-2006, 07:56 PM
Have you experience with Conbraco? I just know of them as the inheritor of Watts' old PVB, their RPZ's are just catalog pages to me. I see Watts is introducing a new Y-pattern that looks like a Conbraco. I appreciate the extra testcock, though. I would still advocate following mfr procedures for draining RPZs, even if you did blow air through them. The older designs had fairly large check valve chambers, and I would want to open one up, after the air, just to ascertain that it really is clear.

I'm assuming there is a point to those mfr instructions/cautions, unless they're just cheesing us off because we don't live in Sunny California where they were made.