Hydronic Heating Help Request: Pressurizing Zone issue.

SkodaZek

Hey folks,

I am a homeowner with a Hydronic heating system. I have 4 zones with honeywell valves/solenoids. This weekend I did a full system flush and bleed (tons of air and corrosion in the lines) and as a result it is functioning much better. Unfortunately I have an issue I am not sure how to deal with. The last plumber we had one mentioned this as well a few years back.

Apparently whoever put in this system (before I owned the house) they attached the utility water in line to the pipe leading into the boiler rather than into the zones/complete system. After fully clearing and bleeding all 4 zones, when trying to repressurise each zone using the standard pressure providing by the inboard water from utility, it sets off the boilers pressure release valve as the water goes into the boiler (regardless of if it is on or off) before it is able to be fed too the other zones of the house.

This is why I think we are having flow issues, I think the system is under pressurized. The boiler pressure gauge goes up and down like crazy depending on if it is heating or if the pump is moving hot water out or not. It fluctates between 10 psi and 25 (15 being ideal for the whole system Im told). Unfortunately I do not have a tool to test water pressure in each of the zones (Isolating and using the bleed valve to verify psi) but due to the aforementioned I believe this is the source of my problem. At current pressures the system seems able to heat 2 of the 4 zones properly. Trying to heat more than 2 at a time leads to lower temp water running through the baseboard radiators.

I would also like to add that there is a valve (closed by default) between the Input pipe (water coming from the zone solenoids into the boiler) and the output pipe (hot water out of the boiler and into the 4 zones). I was thinking prehaps this is what I need to do. Open that valve and then introduce more water into the system. Maybe this would prevent the boiler psi regulator from firing off and shooting out water?

Please let me know what you think.

I wish I could draw a diagram of what I am describing to make it more simple. But if you think you can help and want me to hand draw one and take a picture with my phone camera and send it to you, I would certainly be willing.

Thanks for any help offered.

Zman

Can you take a picture from far enough back so we can see the whole system?
This sounds like a pipe sizing or circulator orientation issue.

SkodaZek

Thank you for responding, I really appreciate it. Below is pictures of my furnace, zone valves, etc.

SkodaZek

Hey folks, just an update. I think the problem is the zone valves. The 2 zones that are cold I think the zone valves are seized. One is partially open (very low heat reaches the first radiator) and the other is fully closed (no heat reaching that zone). I know for a fact that there is no obstruction in the zones as I was able to bleed all 4 without issue so I know that water flows well through all 4.

My zone valves are: Honeywell V8043G1034. Unfortunately I am in a wicked bad financial state atm (hence why I'm self educating and trying to fix this all myself without calling in a professional. To buy these brand new is around 200 dollars each here in Canada.

Unfortunately the valves manual override lever does not seem to be able to open valve. It is completely seized. Is there any other way of simply forcing it open for the time being so the house has heat until I can afford to replace all 4? Is there a cheaper option for valves that will work for my system without modifying the piping?

Please take a look at the pictures above for reference. Thank you for any help you can offer. We are at -12 atm and its a little chilly in here. We generally get -30 in winter quite often here so I am kinda desperate to get a temp fix in place.

SkodaZek

PS. I use celsius when stating temperature. Not fahrenheit.
-12C currently with -30C as winter norm.

SkodaZek

Now I have no idea what is wrong as I just got one of the Zone Valves functioning and even so, that zone is not flowing properly.

It is either flowing backwards or not at all.

I flushed the entire system the other day including every zone individually. Bled all the air out and replaced that nasty water with fresh.

I really am lost and don't know where to go from here. Any help would be absolutely appreciated. Previous posts in this thread have images of my hydronic heating system as well as more details on problems.

JohnNY

You need as much cold pressure as is needed to fill the system to the top of the highest radiators, plus about 5 PSI. 1 pound of pressure raises water 2.31 feet, or about 28 inches, so you can do the math.
The fluctuations on the gauge are likely because your expansion tank is either improperly charged or ruptured.
Stand back and take a wide, floor-to-ceiling picture of your boiler from the front and left side, please.
Post those pics and check back here.

psb75

There are likely, multiple issues with your system. You are presently starting to get good information. Be patient and answer the questions posed to you from this forum. Providing better pictures will help...you.

Zman

Did the problem start after you bled the system?
Do the relief valve and gauge only spike when you are filling it?
When you are bleeding it, are you closing the red gate valves and putting the hose on the blue boiler drains?

EdTheHeaterMan

In order to understand your system so you can do the DYI repairs you should look at this booklet (its free) http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf I used it to teach a one day seminar on Hydronics. This is written for the non engineer to help in understanding how the whole thing works.
I see the problem your plumber mentioned about the feed line going into a zone loop. The fact that is id going into a zone loop is not so much the issue because there are no valves between the feed location and the Return inlet to the boiler. What the problem actually is has to do with the position of these three components. The feed location the expansion tank and the circulator. The best configuration is discussed on page 13 of this text however there is no mention of the problems caused by the configuration that you have.

I made this slide to show the problem you have.
Consider that the expansion tank is known as the point of no pressure change in your system. (Take my word for it, because it takes too long to explain herein) so if your tank has 12 PSI air pressure in the air side of the bladder in the tank, and the auto water feed is also set for 12 PSI and you get all the air from all the radiators by purge or venting, then for all intensive purposes the 3 pressure gauges will read about 12 PSI. Without operating the burner, just turning on the pump will cause a difference in pressure between the inlet of the pump and the outlet of the pump.

Since the tank is the point of no pressure change, the gauge near the tank will stay at 12 PSI. the pump outlet will increase in pressure by less than 1/2 PSI. That is to allow for the pressure drop thru the boiler, so let's say the pressure gauge at the outlet of the pump reads 12.4 PSI. That means if the pump creates a pressure difference of about 6 PSI between the inlet and the outlet, the inlet pressure must drop to 6.4 PSI. That is just simple math. if the outlet can only get up to 12.4 PSI and the inlet is 6 PSI lower, then 12.4 - 6 = 6.4 inlet pressure.

Now look at the location of the water feeder. That is set at 12 PSI and the pipe it is connected to is now around 6.4 PSI... If that feeder is operating properly. when the pipe water pressure drops to 6.4 it will try to make it 12 PSI. Eventually that is exactly what will happen (in pretty short order too). That means the outlet of the circulator will be 18 PSI. The expansion tank will become overloaded because it will be holding 18 PSI of water and air everytime the pump operates. But after the first time the pump operates and then stops, that extra water in the expansion tank does not go away. No... Now you have about 17.? PSI as the new static pressure. Each time the pump starts up again, a small squirt of water jumps thru the auto feed valve, and eventually you will get over 20 PSI as the static pressure.

Since most relief valves are set to pop off at 30 PSI, this does not reveal itself as an issue that needs to be addressed. But if this is the way you always do it, you will come across a time when you need a higher static pressure, because you have a 4 or 5 story building. That is when you need to start at 18 PSI to get the system filled with water. If you do that when you are starting at 18 PSI and have a more powerful pump, then you will be very close to 30 PSI and will not understand "Why is the relief valve always discharging on this job?... I did it 50 times on other systems and never had a problem."

So in your situation You may be able to leave the fill valve open and let the auto feed do its job. But if you see the pressure getting too close to 25 PSI, then shut off the feed valve. You can decide to repipe the feed valve near the expansion tank at a later time (Summer Time)

(now you see why I didn't want to explain "Point of No Pressure Change" in this comment. Priv Message me if you want the PONPC discussion.)

Respectfully submitted,
Mr. Ed

SkodaZek

Zman said:

Did the problem start after you bled the system?
Do the relief valve and gauge only spike when you are filling it?
When you are bleeding it, are you closing the red gate valves and putting the hose on the blue boiler drains?

Thanks for your response.
I bled the system as a response to 2 of the 4 zones not working.
The relief valve only fires off while putting water into the system from the town utility/water.
When I bled all 4 zones, I closed the the red valves on the right side of the zone valves for all 4 zones, and used the blue bleeders to flush water through the system at full utility pressure (the boiler relief valve does not fire as long as the water is rushing out of the system through blue bleed valve.

Also of note, I mentioned above. The utility water in is attached to the pipes going into the boiler left of the zone valves. So fresh water has to go through the boiler and up through the zones then it comes out of the bleed on its way back to the boiler. The blu bleed valves are about 6 inches to the right of the zone valves.

As requested these are pictures from floor to ceiling.

SkodaZek

Yes that is me wearing winter jacket in doors little chilly in here atm. As you can see I have also destroyed this square section linoleum floor with all the water from the flushing (drain is in center of floor).

neilc

you're purging with the boiler and circulators turned off,
correct?
and all the thermostats turned off, low heat, 55*F,
correct ?

does the manual lever on all the now closed zone valves have a resistance to them as you would try to manually open each?
if yes, then good, the zone valves close,
do they all open manually?
there would be resistance on that lever as you swing it open,
yes? good,

let's purge,
all valves open except for the 4 zone valves, and close that bypass between the supply and return, just above the boiler,

start at the distant zone from where the makeup water feeds into

put your hose on a purge bib up at the zone valve, and open the bib,
open the fast fill to keep pressure up until the hose runs air free,
now open that zone valve manually a couple times and burp any air behind it,
no more air on that zone? good, leave the zone valve closed,
close the fast fill, and then close that purge bib,

move to the next zone, and repeat,
do all 4 zones,

open the bypass above the boiler,
start the boiler and turn up the thermostats,

circulator is working,
correct?

HomerJSmith

I didn't read all the comments, but just breezed them. If I read them, I would fall asleep and not wake up for two days. So, if there is duplication, please, forgive me.

First, you should have checked the air pressure charge on the expansion tank and set it at 12-15 psi.

You probably need to close that bypass (white knob) gate valve between the boiler supply and return. Be sure and count the revolutions so you can return the valve to the original setting.

You need to purge one zone at a time until is no longer spouting air or the hose jerking in your hand. It may take some time.

Street pressure (50+psi) will blow the boiler PRV (30 psi max) every time unless a path of escape for the higher street pressure exists, like a hose from the boiler drain valve into a sink.