Heated water getting past circulators when heat is off

julianne_lynne

Hey guys! First ever post but this issue has been bothering the heck out of me for far too long. I have a slant fin Liberty oil fired hot water boil w/ tankless coil. Domestic hw supply and 2 circulated heating zones w/ non-IFC taco pumps. 

Boiler must maintain 180 degree min at all times for domestic supply.
In the summer, zone 2 piping is hot above the circulator pump while zone 1 is cold. Being that the writing on the black pump is upside down I initially though, duh. It was installed upside down. But then looked at the arrows on both pumps and both are pointing in the same direction. 

I had 2 different companies come out (for quotes to install LWCO) and both said I needed to eliminate the flow chek and replace pumps with IFC pumps. 

But I just haven’t been able to wrap my head around why heated water is getting past 1 pump and not the other!? I just noticed something odd though.. one of the pumps reads “WOB” above the arrow while the other says “HRT”

What do these abbreviations mean and why are they different? Or ANY other insights??

i should also note that while we have 2 zones- even if only zone 1 is calling for heat, zone 2 heats up to nearly the same temp regardless.

UPDATE:
hi all! I just wanted to thank everyone for their input! I ended up swapping out both circulators with IFC circulators and that seems to have solved the problem. I am now able to run the zones independently as well which is great and definitely helping with efficiency and oil consumption. Thank you all!!

BDR529

Bad check. Use valve to confirm.

julianne_lynne

Thanks for the response! The flow check is on the completely opposite side of the system though and this occurs during the summer months when heated water is not being circulated through the system. 

See where the 2 zones converge below the circulator pumps and the large pipe goes into the boiler- of course the water sitting in that section of piping will be always be hot as the boiler must maintain its 180 deg. year round. But for some reason, and this is where I’m perplexed, the hot water is continuing to heat past (above) the circulator pump, while the other circulator keeps the heated winter contained. So it’s as if one valve were open and one were closed. However they’re both open and neither circulator has an internal flow check. 

I wish I could explain it better. Maybe I can post a video?

julianne_lynne

And doesn’t it seem odd that the writing on one circulator is upright while the other is upside down? Just seems way too coincidental?
 

Big Ed_4

I am assuming there are two flow valves on the supply piping to each zone ? The one zone with the bypass , The flow valve needs to be cleaned . The bonnet has to be removed and the weight surface , the stem the weight rides on as well of the valve seat needs to be cleaned with fine steel wool .

HVACNUT

The only concern is the direction of the arrow on the volute. They're both pointing down so you're good there. A bypassing flo valve was mentioned, and that's where the issue lies. 

julianne_lynne

Ok thank you! That’s good to know. And I apologize I meant to post a picture of the entire system. I’ve added it to this comment below. Does the picture change your first response at all? I don’t know much but I’m I’m trying my best to learn so any advice at all is welcome and appreciated. I know the system is not right in many ways, I just can’t definitively explain why or how which drives me nuts. So I’m all ears! 

FC= Flow check
the thermal imager is just a pic from July showing how one zone is hot. 

EdTheHeaterMan

You are experiencing a Phinomon called Ghost Flow (we get this a lot around the end of October). It is explained in this text bookhttps://documentlibrary.xylemappliedwater.com/wp-content/blogs.dir/22/files/2020/01/FH-Z100B-BG-Zoning-Made-Easy-2.pdf starting on page 10

The fix is to use a flow control valve on bo the the supply and return. You may be able to just purchase the check valve that fits in the existing pump. https://www.supplyhouse.com/Taco-006-047RP-IFC-Replacement-Kit-for-Select-Taco-00-Series-Cartridge-Circulators This one is supposed to fit the Taco 007-F5. It will not fit the older pumps since they were built before the IFC pumps were invented, but your pumps look to be the newer style.

EdTheHeaterMan

As far as the WOD and the HRT is concerned, they were cast in a different batch. The black one came with the boiler, the green one was purchased separately from the supply house stock. Both the same pump!

Big Ed_4

I only see one flow valve , there should one be for each zone . To fix the mistake , either repipe the supply and add a flow valve per zone or add two spring check to each of the returns . Which comes with an IFC Taco . Since there is no problem with the circulators . I would just add the checks ..

julianne_lynne

Big Ed_4 said:

I only see one flow valve , there should one be for each zone . To fix the mistake , either repipe the supply and add a flow valve per zone or add two spring check to each of the returns . Which comes with an IFC Taco . Since there is no problem with the circulators . I would just add the checks ..

Thank you! I have wanted to re pipe the system and get it set up right for several years now so I finally had 2 companies come out for quotes and I mentioned having a flow check on each zone and they both said no it’s not necessary. I literally have been driving myself nuts for weeks trying to understand how it’s not necessary and it just didn’t make sense so thank you for mentioning that.

Do you know if the circulators are on the correct side? 

julianne_lynne

EdTheHeaterMan said:

You are experiencing a Phinomon called Ghost Flow (we get this a lot around the end of October). It is explained in this text bookhttps://documentlibrary.xylemappliedwater.com/wp-content/blogs.dir/22/files/2020/01/FH-Z100B-BG-Zoning-Made-Easy-2.pdf starting on page 10 The fix is to use a flow control valve on bo the the supply and return. You may be able to just purchase the check valve that fits in the existing pump. https://www.supplyhouse.com/Taco-006-047RP-IFC-Replacement-Kit-for-Select-Taco-00-Series-Cartridge-Circulators This one is supposed to fit the Taco 007-F5. It will not fit the older pumps since they were built before the IFC pumps were invented, but your pumps look to be the newer style.

Thank you Ed! That was my next question. Whether or not it’s okay to have flow checks on both sides. I couldn’t think of any other alternative to prevent the mixing. Currently, I really only have 1 zone. Both work and function however regardless of which zones calling for heat, both zones heat to nearly the same temperature. I understand why but am just not totally sure how to fix it. And it infuriates me how inefficient it is right now with the zone mixing.

I would like to cut everything out and start from scratch to get it right. Unfortunately the 2 companies I had come out for quotes on doing so, we’re $2000 and have completely wrong info so I’ve been trying to determine the correct sequence. But the more I learn the less confident I become. 

Note;
For some reason, in the winter months, we’re unable to take a hot shower from start to finish. It will start off hot, cool off to Luke warm, then gradually get hot again, then luke warm, hot, repeat. In the summer it’s not an issue however I do close the valves on both zones during the summer.. not sure if that is relevant though?

HomerJSmith

Boiler must maintain 180 degree min at all times for domestic supply.

which means that you have a tempering valve in the domestic hot water sys. These valve need cleaning or replacing especially so in hard water areas and is most probably the source of the changing water temps when showering. The valve may be slow in responding to the changes in flow temperature. Just a thought.

julianne_lynne

HomerJSmith said:

Boiler must maintain 180 degree min at all times for domestic supply.

which means that you have a tempering valve in the domestic hot water sys. These valve need cleaning or replacing especially so in hard water areas and is most probably the source of the changing water temps when showering. The valve may be slow in responding to the changes in flow temperature. Just a thought.

I will have to look into how to do that, thank you so very much for commenting as I’ve never been able to determine the cause. We have extremely hard water and even worse, a deteriorating steel well casing (I was told by well company that it was the casing but I went down 16’ with my borescope and the casing was still all plastic). Regardless though, there are huge chunks of rust in our water supply. We installed a whole house filter (cheapo one, going to add spin down soon) and this is what comes out of the filter every few months (picture below). i was EXTREMELY concerned about damaging boiler when I discovered the magnitude of rust but local HVAC pro told me it’s not possible to cause any damage or disruption internally, which I couldn’t wrap my head around. 

HomerJSmith

With that much scale you definitely have a problem.

i was EXTREMELY concerned about damaging boiler when I discovered the magnitude of rust but local HVAC pro told me it’s not possible to cause any damage or disruption internally, which I couldn’t wrap my head around.

What he means is that the boiler is a closed sys. The boiler isn't open to the well water. What is the composition of that sink debris?

julianne_lynne

HomerJSmith said:

With that much scale you definitely have a problem.

i was EXTREMELY concerned about damaging boiler when I discovered the magnitude of rust but local HVAC pro told me it’s not possible to cause any damage or disruption internally, which I couldn’t wrap my head around.

What he means is that the boiler is a closed sys. The boiler isn't open to the well water. What is the composition of that sink debris?

Hm I’m confused. How is it not exposed to the well water? The water comes from the well, flows through the coil and comes out hot (domestic hw  side). In the last picture, the filters are from my washer. The water passing the blue filter comes directly from the well straight to the washer whereas the water passing through orange filter goes through boiler then to the washer and that filter has has significantly less sediment on it. So where else would it have gone? I don’t get this and it’s killing me lol

the sediment is rust flakes from the well casing. The pictures are of what I removed from the whole house filter 

julianne_lynne

HomerJSmith said:

Boiler must maintain 180 degree min at all times for domestic supply.

which means that you have a tempering valve in the domestic hot water sys. These valve need cleaning or replacing especially so in hard water areas and is most probably the source of the changing water temps when showering. The valve may be slow in responding to the changes in flow temperature. Just a thought.

Is tempering valve the same as mixing valve? If so, how does its response vary? I thought mixing valve essentially just remains open to allow a certain amount of cold water to mix with the hot water. Is there more to it then that? I thought it just always remained in the same position internally?

Larry Weingarten

Hi, Mixing and tempering valves are basically the same thing. They adjust in different ways to water temperature, so mix different ratios depending on what temperature you want and the hot and cold temps feeding the valve. Hope that makes sense.

Yours, Larry

PS limescale can really mess with the internal workings of these valves.

bburd

A thermostatic tempering (or mixing) valve is required by most current plumbing codes for tankless coils. Before this requirement it was typical to install a globe valve bypass between cold and hot on tankless coils to temper the very hot water from the boiler, but with no thermostatic function.

After a lot of people got scalded…the code was changed.

julianne_lynne

hi all! I just wanted to thank everyone for their input! I ended up swapping out both circulators with IFC circulators and that seems to have solved the problem. I am now able to run the zones independently as well which is great and definitely helping with efficiency and oil consumption. Thank you all!!

Mad Dog_2

The Black Tacos come with the boiler Burnham,, Peerless,, WM et al . Their green , identical Taco green circs are supply house bought.  Black 1978 Corvette stingray versus Green 1978  Corvette Stingray (yuck). No difference to a blind man.  Mad Dog