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[tinfoilhat2020]

so I recently upgraded from a 15-58 to a 26-99 for the house loop. While using the 15-58 on high setting, my Delta T when DHW and Furnace were calling for heat was 40-42F (20 for furnace and approximately 20-22 for DHW) which is WAY to high IMO. So I bumped up to 26-99 and installed a few days ago. With pump set on medium setting I am now at a 30-32F delta when DHW and furnace are both calling for heat at the same time (15 for furnace and 15-17 for DHW). Is this sufficient or should I bump that sucker up on High setting and get the delta down even lower? I don't want to move the water so fast that it cools the register temps either.....anyone got insight here??? my only concern with running a Delta on the higher end is that when the water temp at the boiler is down around 160-161 and getting ready to fire, if everything in the house calls for heat....I will see return temps around 130ish...which, IMO is way to low. I have a g200 and it has been recommended that I don't mess with the temp settings as it has a high limit shut off set at 190. I think the factory settings are 160-180, and probably for good reason. My old heatmor I ran at 175-190 and had it dialed in at a Delta of 23F when everything in the house was calling, I was running a B&G-36 on high setting. so, even when water temps were at 175, and everything at house was calling, I was only seeing the lowest return temps at around 150-152F.

I feel like im over analyzing, but after making another HUGE investment in a new set-up, I want to do everything I can to ensure a long boiler life.

any input would be appreciated.

Thanks!

[slimjim]

What you are forgetting is that as your temperature of the boiler water cools to around 160, the differential between your heat load and boiler water are also closer so the transfer of heat also reduces therefor the return temps to the boiler will not drop as much. Also keep in mind that it will be a rare occurrence for your domestic water and full heat to both be calling under full load, I personally would be fine with the setup you have now. They also should allow you to bump up your temp to 185 and tighten up the differential to 10 degrees if you want to, they did for some of my customers who had troubles with water temps of 160.

[tinfoilhat2020]

Thanks Slim.  I used to run a much tighter differential at my previous house because we had a radiant baseboard system. Even running at 165 to 180 or 170 to 185 would make me feel better. Thanks for your input.

[E Yoder]

I haven't ever had an issue with a large intermittent delta affecting the furnace. I wouldn't sweat it if it heats well in the house.

[slimjim]

I think that's the point Eldon, IF it heats ok then by all means it should be fine but the ability to turn it up in some cases like I typically find here in the Northeast is sometimes very beneficial to the customer.

[wreckit87]

Not familiar with the G or their controls, but it seems to me a tighter differential would alleviate most of the issue at hand if it's possible. As Slim said, the delta will change as the water temp drops also so even at 160, you'll likely still be well above condensation temps. Wouldn't hurt to just grab 3rd gear for a day and monitor the delta either if you wanted. Odds are slim that it'd cool your register temps much if any IMO, but I haven't monkeyed with that enough to have facts.

[tinfoilhat2020]

thanks guys. i may just turn it up for a day and monitor, see what it does.

[E Yoder]

I took it that he was concerned about creosote in the outdoor furnace caused by low return water temps. If it causes too low temp water in the house then that's a different issue, I agree.
Is this a forced air system or a boiler? I probably missed something.

[tinfoilhat2020]

I took it that he was concerned about creosote in the outdoor furnace caused by low return water temps. If it causes too low temp water in the house then that's a different issue, I agree.
Is this a forced air system or a boiler? I probably missed something.

I have a forced air system...I get great heat through the furnace even when water temp is at 150, I was more concerned about low return temps causing sweating and destroying the boiler over time. For example, my G200 is set at factory temps at 160-180. so when boiler was is idling at 161 and I give my kids a bath and the furnace is running at the same time...I have a 30-32F Delta, so the return was is approximately 130F (161-31). now, like was stated Its not that often that DHW is getting drained on and furnace is calling at the same time....im probably way over analyzing things....but when you make a 14k investment (again) you just want to make sure you are doing everything you can to prolong the life of the boiler. I have always been told that the motto for boilers is "run them hot and run them often."

Now, what is also different about this G200 system is the insane amount of mixing that is going on in the water jacket, including the shunt pump I have 3 pumps running at all times....so even if I have colder water returning from the house, it is getting instantly thoroughly mixed with hot water. I am not overly concerned, just wanted input from the group as I am no pro. I just want this investment to last as long as possible!


Thanks Guys!

[E Yoder]

Yeah , with three pumps running your delta on the inside of the water jacket on the return is much smaller and it's spread out to mix better. The tubes that the return water is hitting are 409 SS.
The larger 20 temp swing is to encourage long burn cycles which help keep creosote down. You could adjust it if you want to I guess.
I used a temp monitoring system this summer for a while and saw 40+ degree deltas on my system when we ran multiple showers at once.
But I agree about it being a big investment. I'd be quicker to test water quality more often than any other preventive maintenance.

[slimjim]

GOD knows I'm not going to speak again about the longevity or lifespan of these stoves, I get into trouble when I do,  I'll leave that up to the guys who build and sell them but after initial warm up, I will say that I haven't seen any of them have condensation issues above about 120

[mlappin]

One issue I do know off and I heard this from my distributor. But should never be an issue with a stove with adequate flow, my distributor had to service a stove once that the turbolators were stuck and stuck good, got em free then had the issue again. Turns out whatever the previous stove was only had 3/4” lines, then that one lineset serviced a few building and everything was in series. Basically returning water back to the stove barely above 100 degrees sometimes, that definitely caused a cold spot around the heat exchanger tubes. Least that was how I understood it, they added another pump to circulate more warm water around the tubes and tee’d the return into that so it would mix more with the suggestion that the underground be changed out to at least one inch.

[slimjim]

That's exactly the reason for that bypass loop that so many manufacturers are putting on their boilers now, flow rates can be restricted and the boiler won't be hurt by the cold return, one of the scrapped boilers that I sent back to corporate via bens yard had that very issue, 1 inch nominal cheap waterlogged pipe, 120 foot run in one direction and 3/4 inch black iron street 90s on the house end. Good move on their part!

[tinfoilhat2020]

I run all one and a quarter inch underground pipe and 1 inch copper inside every building so I think my flow is good