System has issues

ChipDryden

The installer can't seem to get this system to run properly. The DHW tank blows water out of the relief valve, there is also water noise such as dripping and whooshing sounds coming from the pipes, any advise would be appreciated. Thank You

heathead

The pump for the water heater should be installed horizontal. What size pipe is going to that heater it looks small. My guess for the noise is the pipes need to be purged of air. What pressure is the boiler water at? The bucket is under the relief valve for boiler. The system should be about 12-15 psi for most homes.

Jamie Hall

Also, what pressure is the expansion tank set for? It must be set at the cold system pressure when it is empty and not connected to the system.

EdTheHeaterMan

I have a feeling the zone circulator pumps are upside down. Look at the arrows for the direction of flow on the 4 zone pumps in the last picture. They should be going up. I think they are going down but I can't be sure by the picture. Should be an easy fix because there are valves everywhere. Nice job BTW.... If it would only work nice!

Tell your installer to draw the arrows on the inside of the pipe (not the outside like in the first and second pic) so the water can see it and know which way to go.

Alan (California Radiant) Forbes

Your installer has done a nice, neat job, but the finer points of piping a hydronic system have been overlooked.

Both of your problems have to do with air remaining in the boiler. Without removing the air, the circulator cannot move the water through the boiler's heat exchanger, so it sits there and overheats. Eventually, it starts to boil, the pressure goes up and the relief valve dumps.

There are other problems as well and they will reveal themselves once water flow is achieved. Some are:
- pipe size to the indirect is too small.
- closely spaced tees aren't spaced closely.
- pump mounting is not as required by the manufacturer.

mattmia2

I think you can turn the body of the pump around in the piping and turn the motor around on the body so you can keep it mounted the same with the pump itself reversed.

Zman

@ChipDryden
Are you still with us?
The DHW is likely blowing off due to a lack of domestic expansion tank.
Is the boiler going to 90 degrees then shutting down with no error message? If so, the boiler may be set for 90 degrees which would be an easy fix. Do you have an outdoor temp sensor wired? Is this a radiant system or baseboard? Can you feel a temp difference on the supply and return zone pipes?
As far as the gurgling noise goes, there are some minor errors in the piping which make it difficult to purge. Does the zone pump indicate weather a internal check valve was installed?

Ironman

In addition to the other things noted, it appears that the "system" sensor has been improperly located at the boiler's return line. It should be downstream of the closely spaced Tees, after them, but before the MBR (air separator).

hot_rod

It can be a pain getting the air out of the top of those Nobels. On mine I held the relief valve up top open for about 10 seconds, purge int that bucket you have.
Since the air sep is in the other loop the boiler may not be getting purged adequately.

mattmia2

Probably why HTP provides a separate automatic air vent in the boiler.

Zman

I think we have a One Post Wonder...

hot_rod

mattmia2 said:

Probably why HTP provides a separate automatic air vent in the boiler.

I think most all mod cons have an auto or manual vent on the HX.
But it's not the wide, low velocity zone like cast iron sectional, so they are not so effective. Even the fire tubes have some hefty velocity, to scrub heat from that thin metal. They need turbulent conditions.
A vertical air sep right under the wall hung mod cons works best.

ChipDryden

Sorry folks for the delay, I really appreciate all the posts.

ChipDryden

The contractor said these modern boilers won't heat up the house when the air temp outside is in the 60's because of the outdoor sensor??? Is this true with this kind of system?

Zman

So the DHW mystery is solved. The indirect piping is a little small but not the cause of the problem. The zones have check valves, the purge points look good.

It sounds like your boiler is functioning correctly it is just not set to go hot enough. The sensor mounted on the condenser is not good, is it also in the sun? Does it appear to be reading correctly?

Someone should dig into the ODR settings. For base board, the low boiler temp should probably be around 120 and the design day more like 180. Baseboards put out very little heat at 90 degrees.

ChipDryden

Thanks, He said he will look at the sensor location.

hot_rod

As for the outdoor sensor, scroll through the menu on the boiler and it will show what temperature it is reading. You want it in a shaded spot so it reads actual ambient air temperature and not be influenced by the sun.
If it has to be on that side of the house, get it up,under the eves, out of any sunlight.

Ironman

The Out Door Reset (ODR) function of the boiler varies the boiler's supply water temp (SWT) based upon outdoor temp: the colder it gets outside, the warmer the water and vice versa. This saves energy and increases comfort, but as @Zman said, the lowest water temp setting should be 120* for standard baseboards (unless they're over-sized).

It also has a Warm Weather Shut Down (WWSD) function which prevents space heating around 68-70* outside because the house doesn't need heat at that temperature.

The outdoor sensor should be mounted on the north side of the house, out of direct sunlight, not inside the Mitsubisi.

As a side not, the Mitsubisi should not be that close to the house; it should have at least 16" clearance to breath properly. It also needs 24" on the right side for servicing. Somebody didn't read the instructions.

ChipDryden

I was also thinking the sensor shouldn't be anywhere near the Mitsubishi unit.

MaxMercy

ChipDryden said:

I was also thinking the sensor shouldn't be anywhere near the Mitsubishi unit.

I agree. Ideally, it should be on the North side of the house to limit solar gain. I have one of those remote thermometers, and I put the sensor between the window and window screen on my front porch which faces east until I get a weather proof enclosure for it. On a calm day in the winter when it's 35F outside, my front porch can read 65F in the mid morning until the sun is out. In the summer, it can reach over 90F on a 60 degree morning.

ChipDryden

Update, The contractor agreed to move the sensor, change the pump orientation and install an expansion tank on the DHW tank. They are also going to spend more time purging air out of the system.

ChipDryden

Admittedly, I am somewhat confused how to purge the air since the drain cocks are on the feed side, I would think they would be on the return side.

Ironman

They're flow checks, but with the purge valves located on the supply side, they're gonna prevent purging since it would have to be done with water feeding from the return side.

The contractor needs to install boiler drains on the returns that don't have them like the two blue ones on the middle returns. Then, the loops can be purged from the supply lines out through the returns. The check valves need to be left alone which will allow water to pass through them.

It just a simple matter of picturing the flow of water through the pipes in your mind. Unfortunately, some people in the trade can put pipes together but not think abstractly.

hot_rod

Shut off the yellow handle ball valve below the circs, so water flow would go up the return piping, right side of the circulator, around then stop at that yellow handle valve. The hose bib above it is the purge port.
Yes that red iron flow check needs to be oper, turn lever on top counter clockwise to hold open. Remember to turn all the way down, clockwise after purge.

When purging the bronze colored fill valve should be in fast fill mode, lift handle up. need to keep pressure under 30 psi as you purge in fast fill or the relief will pop.

Might have the installer do them purge for you?

ChipDryden

Thanks!!!