Garn system questions

[Rick Stanley]

oops, that first shot in last post is wrong

 

[Rick Stanley]

Can I go from here to here? Can I connect the two ends of the headers together?

 

[BrownianHeatingTech]

Can I go from here to here? Can I connect the two ends of the headers together?

Yes, that was the suggestion.

You need a pump to create flow through the loop, obviously. The advantage is that it will be needed when you replace the existing boiler, anyway, and it will keep the boiler hot (tees in the return will only transfer heat into the boiler when a zone is running).

Joe

 

[Rick Stanley]

Can I go from here to here? Can I connect the two ends of the headers together?

Yes, that was the suggestion.

You need a pump to create flow through the loop, obviously. The advantage is that it will be needed when you replace the existing boiler, anyway, and it will keep the boiler hot (tees in the return will only transfer heat into the boiler when a zone is running).

Joe

So, can the Hx be in that loop with one pump pushing water through the whole works
( the boiler, both headers and the hx) OR does the hx loop need to be tee'd into the boiler loop?

 

[BrownianHeatingTech]

So, can the Hx be in that loop with one pump pushing water through the whole works
( the boiler, both headers and the hx) OR does the hx loop need to be tee'd into the boiler loop?

Either can work. Having the HX separate gives a greater degree of control, but requires a second pump. It's a balancing act.

Joe

 

[Rick Stanley]

So, can the Hx be in that loop with one pump pushing water through the whole works
( the boiler, both headers and the hx) OR does the hx loop need to be tee'd into the boiler loop?

Either can work. Having the HX separate gives a greater degree of control, but requires a second pump. It's a balancing act.

Joe

Control of what? When each pump starts? Pump speeds?

 

[BrownianHeatingTech]

So, can the Hx be in that loop with one pump pushing water through the whole works
( the boiler, both headers and the hx) OR does the hx loop need to be tee'd into the boiler loop?

Either can work. Having the HX separate gives a greater degree of control, but requires a second pump. It's a balancing act.

Joe

Control of what? When each pump starts? Pump speeds?

Yes.

The best flow rate through the HX may not be the best flow rate for the primary loop.

Similarly, when the backup is running (in the future, after removal of the current boiler), you may not want flow through the HX, so having that on a separate loop would prevent that.

Joe

 

[Rick Stanley]

Another plan was to cut two close tees in here and be done with it. Might be simple enough..................

Rick, if that is your return leg, that is where I would (and did) put in the close Tees and valves. Here is my splice:

I should have some more pics posted of the HX connections and piping soon. I'll also have my control schematic finalized and posted soon, too.

Jim,

I see, in your pic, that you have a ball valve between the close tee's in the return of the boiler. Normally, in drawings of p/s piping arrangements I don't see that. Now that your new system is running, do you have that ball valve closed to ensure that ALL of the return water MUST go to the Garn HX to be re-heated before re-entering the boiler?

Thanks,
Rick

 

[Jim K in PA]

Jim,

I see, in your pic, that you have a ball valve between the close tee's in the return of the boiler. Normally, in drawings of p/s piping arrangements I don't see that. Now that your new system is running, do you have that ball valve closed to ensure that ALL of the return water MUST go to the Garn HX to be re-heated before re-entering the boiler?

Thanks,
Rick

10-4. It is probably not necessary, but I decided to install it anyway. I wanted to ensure 100% flow through the HX. It is not really a P/S piping setup on this side, just a diverter to the HX. I only have the original little TACO 007 pushing water through that leg into the HX and then into the boiler, and then into the zones (high head, ya think?). It'll all be revised when I delete the oil burner in a year or two anyway.

 

[Rick Stanley]

Jim,

I see, in your pic, that you have a ball valve between the close tee's in the return of the boiler. Normally, in drawings of p/s piping arrangements I don't see that. Now that your new system is running, do you have that ball valve closed to ensure that ALL of the return water MUST go to the Garn HX to be re-heated before re-entering the boiler?

Thanks,
Rick

10-4. It is probably not necessary, but I decided to install it anyway. I wanted to ensure 100% flow through the HX. It is not really a P/S piping setup on this side, just a diverter to the HX. I only have the original little TACO 007 pushing water through that leg into the HX and then into the boiler, and then into the zones (high head, ya think?). It'll all be revised when I delete the oil burner in a year or two anyway.

Makes sense to me. I have a similar set-up, but with a Taco 007 on each of the seven zones, pumping away. When I look at the possibility of putting close tee's in the return leg I always wonder what would keep the water
(at least of of it) from shooting past the tee's and into the boiler again without going through the Hx, even with an added pump between the tee's and the hx helping out. Since my goal will be to keep the boiler hot for inhanced dhw production with less (hopefully none) oil use and it's not p/s anyway, I like the ball valve there.
(maybe could use some kind of automatic valve)

I wonder how low I can let the oil boiler temp get and still make dhw??

 

[Jim K in PA]

Makes sense to me. I have a similar set-up, but with a Taco 007 on each of the seven zones, pumping away. When I look at the possibility of putting close tee's in the return leg I always wonder what would keep the water
(at least of of it) from shooting past the tee's and into the boiler again without going through the Hx, even with an added pump between the tee's and the hx helping out. Since my goal will be to keep the boiler hot for inhanced dhw production with less (hopefully none) oil use and it's not p/s anyway, I like the ball valve there.
(maybe could use some kind of automatic valve)

I wonder how low I can let the oil boiler temp get and still make dhw??

Rick - the dhw coil in my furnace is the exact reason I went this way. However, the dhw situation is the biggest disappointment I have so far. The amount of heat transfer to make 120 degree hot water through that little coil is staggering. Unless my GARN supply temps are above 170 AND there is at least one, and preferable two, zones circulating, a shower will bring down the boiler temp below 140 pretty quick and the oil gun will kick on. It shuts off before the shower is done, typically, or within 30 seconds of shutting off the hot water. The amount of oil used is relatively small, but it still annoys the crap out of me. I think Tom Caldwell said he put a 1/2" bypass line and a ball valve between is supply and return legs to keep hot water flowing through the furnace and the coil hot. I am going to delete the oil burner next year and install an indirect wh.

 

[Rick Stanley]

Makes sense to me. I have a similar set-up, but with a Taco 007 on each of the seven zones, pumping away. When I look at the possibility of putting close tee's in the return leg I always wonder what would keep the water
(at least of of it) from shooting past the tee's and into the boiler again without going through the Hx, even with an added pump between the tee's and the hx helping out. Since my goal will be to keep the boiler hot for inhanced dhw production with less (hopefully none) oil use and it's not p/s anyway, I like the ball valve there.
(maybe could use some kind of automatic valve)

I wonder how low I can let the oil boiler temp get and still make dhw??

Rick - the dhw coil in my furnace is the exact reason I went this way. However, the dhw situation is the biggest disappointment I have so far. The amount of heat transfer to make 120 degree hot water through that little coil is staggering. Unless my GARN supply temps are above 170 AND there is at least one, and preferable two, zones circulating, a shower will bring down the boiler temp below 140 pretty quick and the oil gun will kick on. It shuts off before the shower is done, typically, or within 30 seconds of shutting off the hot water. The amount of oil used is relatively small, but it still annoys the crap out of me. I think Tom Caldwell said he put a 1/2" bypass line and a ball valve between is supply and return legs to keep hot water flowing through the furnace and the coil hot. I am going to delete the oil burner next year and install an indirect wh.

Jim- that is interesting. I did not know that about Tom's set-up. But, if you look back earlier in this thread you'll see where Joe Brown suggested that very thing. I don't think he meant a little 1/2" line though. I took him to suggest an 1-1/4" or something big enough to provide some volume of water moving through there to keep the whole works hot, supply header, return header, oil boiler and hx all in a big loop. I'm not clear on the details of doing that, but at least, so far, thanks to you, I know that I probably won't get enough hot water from just teeing into the return, even with the 60 plate I've been sized for. I still wonder if the recovery will be fast enough on a big call for dhw. What do you think?

 

[TCaldwell]

rick, the 1/2'' bypass is primarily to allow minimum flow through the boiler during the summer months so when the indirect fired water heater calls,it does not pull cold water through the oil boiler and trip the aquastat to fire. one cause possibly for your oil boiler firing when the garn is hot could be that if multiple zones call at the same time, multiple zone circ flow is greater than the flow of the circ supplying the closely spaced tees. basically the cold return water flow is displacing more volume ,and ending up with the diluted hot supply water and short circuiting through the boiler instead of going to the hx. i have 7 zones with 007 circs and the closely spaced t or injection loop has a 009 it runs 24/7 even with delta t s over 40deg and momentary btu transfer over 300k the oil boiler will not fire unless supply temps are very low 130s. i have a large 30 plate hx with 1.5'' fittings. my suggestion would be to increase flow with a larger circ in the injection loop and possibly remove the ball valve between the closely spaced ts, the farther apart they are the less effective the injection loop becomes.

 

[Rick Stanley]

Tom,

Just to clarify, I haven't hooked my system up yet. I have a Garn 2000 sitting in the shop 200 ft. away and the trench work between here and there is done.

The rest of the system is still in the planning stage. I'm working on wood this winter (got a pretty good pile started) but want to start rounding up pipe fittings, valves, etc now so I can start putting it all together during the warmer season.

I'm trying to address the dhw issue at the moment (again, I keep coming back to it)) and was leaning toward what Jim has done ( keep my oil boiler with dhw coil hot with the Garn heated water) but he's not getting enough dhw. So..............................still head scratchin

Anyway, Jim says he's going with an indirect dhw heater next season and you say that you have indirect too. Maybe that's what I should be shooting for.

How do you have yours plumbed? What do you recommend Tom? Jim?

 

[TCaldwell]

rick,the reason i went with the injection [cloesly spaced ts] and indirect fired hw was that i did not want to keep the oil boiler up to temp all summer just for dwh. with a indirect fired hw , plumbed as any other zone, i fire the garn about twice a week, it serves 2 teenage girls a wife and me, it is made by vaughn 55 gal capacity i think about 700 bucks.

 

[Jim K in PA]

Tom - do you have a diagram of your system you can post, or a picture? If you have already posted one here, let me know and I will search for it.

Rick- Yu have the luxury of time, so if you also have the budget, I suggest going with the indirect like Tom has from the beginning. I did not due mostly to time constraints, and the fact that I inherited a horribly installed distribution system in my old farmhouse that needs to be corrected. My goal was to get my GARN up and running for this season with as little impact on the original, poorly set up zone system. That is because it was and is my intent to eliminate the oil furnace entirely, at which time I will re-pipe the zone manifolds and install the indirect wh.

Tom - my system is currently working through a 20 plate HX with 1" fittings (stepped down from 1.25" on both sides). That is one of my biggest issues at the moment, I feel. I have a 50 plate with 1.25" fittings sitting on the shelf waiting to be installed.

 

[TCaldwell]

jim,rick---------- i will have time tomorrow night to draw and post a diagram of my system layout, kids b ball games and projects today, tom