Weil Mclain Ultra/DHW Issues again

Ringo311

My DHW is pushing out scalding hot water - much hotter than normal. Our faucets all have to be almost completely turned to cold to take a shower.

I checked my system out and the demand for heat is almost always taken up by the DHW. As a result, my heating system cant keep up with the cold temperatures outside and its mid 60's in my house.

The first winter I had the ultra/DHW system (which was winter 10/11), I had the same exact issue. The company replaced the thermostat first in the DHW, which didn't help and a few days later replaced the DHW completely. I haven't had many issues until now.

I have a feeling these issues are due to a bad installation. I read the manual when we first started having issues 3 years ago and found several things the installer left out which they ultimately fixed. Still they wouldn't install the outside temperature sensor and wouldn't install an air intake to the outside after asking. I was told my house wasn't sealed enough from the air to matter. Lastly, my system has never worked that well at heating the house when temperatures are low.

I really don't know what to do, because Im worried the same problems are going to happen again and again. When I contact the installer today to look at this issue should I expect this will be covered under warranty? I am considering contacting Weil Mclain directly to have a look at the installation just to make sure the boiler itself hasn't been damaged and to make sure the installation is correct. There are still a couple things done different from the manual? Any suggestions? I have kids and I don't want them to get burnt by the hot water or get sick because its so cold in here at night.

Boiler wrestler

DHW problems

It sounds like you have a lot more going on than just the domestic hot water issues that lead me to think this might be more than just a bad component. Could you post photos of the near boiler piping.

Ringo311

photos

[u][color=#0066cc]http://ringo311.wordpress.com/boiler-photos/[/color][/u]



A link to my blog with a page of photos.

Zman

Aquastat

Do you have an aquastat or a sensor on the DHW.

Disconnect the DHW wire to isolate the issue.

Carl

Ringo311

Dhw

I have been on the phone with Weil McLain and the installer today. The installer is already trying to run up the bill on me.



Weil McLain mentioned adding a mixing valve on the DHW.



I also noticed the pressure relief valve is weeping water (and the valve is rusting). I looked at the troubleshooting guide and it pointed toward issues with the expansion tank. When they installed the new boiler they reused a very old expansion tank. They told me it would last longer than a new one.

earl burnermann

Good advice

Disconnecting the thermostat will prove wether it is the stat or not. I have the same water heater and keep it turned down almost completely. Would like to install a mixing valve when I have the time and the money. It is rare when I both though ;-)

earl burnermann

Rel valve leaking

There should be a domestic expansion tank on the unit. Modern water meters now come with back flow preventers. A back flow preventer can cause the pressure to triple from cold to hot.

Ringo311

Tank

Here is a picture of the same tank they left to use as the expansion tank instead of installing a new one.

Ringo311

DHW

I unplugged the thermostat and the boiler demand moved back to my heating zones. The water in the radiant loops were at 140 degrees.

I tested the temperature of the water out of my tap and it was 180 degrees.

Will my hot water tank heat at all if the thermostat is unplugged?

If the thermostat is bad, did the thermostat just go bad or is there an underlying problem?

Ringo311

update

Update: I unplugged the thermostat and the system was still not running normal. The boiler didn't seem to be firing. The water temperature in the boiler zones was 105-106 and the pump seemed to be constantly running.

Any help would be appreciated.

Ringo311

Expansion Tank

A person I have talked to said the issue could start with the expansion tank. The installer did not replace the expansion tank or taco air scoop from the old boiler and left the old piping. He thinks air could be getting into the tank.



If you look at the installation manual for the ultra, the expansion tank is above the boiler but below the air scoop. The manual also calls for an air vent at the tee for the expansion tank. I'm assuming the taco air scoop is not an air vent? Is the large steel expansion tank a diaphragm/bladder type tank?

There is an air vent on the HWH and its pushing out water and corrosion.



Can anyone shed light on this possibility?

earl burnermann

Expansion tank

Usually the old parts that you leave on a new install are the one's that will bring you back to the job. But that old expansion tank and the old Air scoop shouldn't create a problem. As long as you completely drain that expansion tank you should be good. If the tank only drops a small amount of water it may be completely waterlogged. You have to get all 15 gallons out of it or the problem will be right back.



If after completely draining the tank the relief valve starts to leak again in a short time you may have a leak between the domestic and boiler water tanks in your water heater. This can be checked if you have a drain valve between the water heater and the isolation valves of the hot and cold water going to the water heater. Just pick up a presure gauge with a drain connector, They sell them at hardware stores and home depot, connect to the drain valve and open that valve. Next note the pressure on the gauge. Next, shut the isolation valves to the tank's hot and cold water. Check the pressure gauge.



If, with those valves closed, you see the pressure drop, you know the high pressure water from the domestic side is leaking into the much lower pressure boiler side. If this is happening the water heater must be replaced.

Ringo311

ok

Thank you for your reply.

Currently there is no water in the expansion tank. It is filled with air.

They did not install drain valves on either the supply or return to the HWH.

A WM rep has offered to send a new aquastat. I'm still worried there's an underlying issue but perhaps not.

I currently have the thermostat unplugged and the boiler seems to be working ok. Could I just leave the thermostat unplugged or turn off the pump to the water heater? Will the heater just gravity feed?

Zman

One at a time

Your domestic water issue is completely unrelated to the boiler expansion tank. Do you have an aquastat or is it a sensor?

First off, fix the DHW issue.

Is the leaking valve on the water heater or the boiler?

If it is on the water heater it is caused by the tank being too hot. This will resolve itself with the new aquastat.

Carl

Boiler wrestler

wiring/controls

After seeing the piping, it's quite possible that the wiring and programming could have also been beyond the installers capabilities. If this has been a three year problem perhaps finding someone who is qualified to work on this is in order. Maybe Weil Mclain or one of their reps can point you to someone with a little more knowledge in your area.



A stuck check valve or wrongly wired/programmed boiler could give all these problems.

Ringo311

re

I'm beginning to think its the wiring as well. Here's the latest:

Talked to WM rep today and she had me test the aquastat by putting the bulb in 130 degree water and moving the dial to see if it activates on and off and it did properly in all settings.

I stood by the boiler for about an hour today and tested a couple things. Firstly, I was able to activate the house zone and HWH zone while the boiler was in the standby setting. But in both cases the boiler just went from "Prepurge to Ignition to DHW/FTB to Postpurge" in a constant 1 or 2 minute cycle. The boiler didn't fire and the circulator pump for the activated zone continuously pumped. This I can remember happening the whole time we've had the boiler (again mainly at night).

I'm confident this issue along with the system heating the hot water boiler zone to 180 degrees is malfunctioning the entire system. At times it works properly but overall its a big mess. Our boiler worked for a short time today (well it heated the house), which is the confusing thing to me. It seems like the vast majority of the day these two issues arise which is certainly which is causing the unit to underperform.   

Zman

DHW

If you disconnect the DHW wire and turn up the heat does the boiler heat perfectly?

If you jumper the DHW wire does the DHW work perfectly?

A DHW aquastat that is going bad and not making a positive open/close can cause a bunch of electrical gremlins. I am not sure your observations about circ and firing are abnormal. Modern boiler controllers do all sorts of things during normal operations that don't make sense at first. The fact that the boiler is getting stuck in DHW mode makes me think aquastat.

Carl

Ringo311

yes

I disconnected the wire to the aquastat in an attempt to get the boiler to fire and the house zones to warm up but the boiler is still just cycling through prepurge, ignition, FTB, postpurge. The pump just keeps pumping 100 degree water through the pipes.

It is 65 in my house already and dropping at its 11:40 pm.

Zman

Setpoint

What is the boiler setpoint temp?

Ringo311

180

Its set for 180.



Last night we didn't get any heat. The HWH was unplugged but for some strange reason, the air vent above the heater weeped air and water through the night.

Zman

Air

It is sounding like you have an air problem. You have an older bladder style expansion tank. You should not have an open air vent in that system.

I keep asking the same question, what changed?

The system has worked for a while and now it does not.

What is he boiler side water pressure?

You may be to the point where it would a good idea to get some local help on this one.

Carl

Tom_133

Sensors!!

So I tried reading through all this post and gave up, so Im sorry if this has been mentioned.



Have you tried unplugging the outdoor sensor, to get the boiler to fire up to the setpoint? I know it wont affect the DHW but he said even unplugging the dhw call it still wont come up to temp.

Ringo311

working for now

So a serviceman came over from the installing company.

Firstly, he cleaned off the igniter and the boiler began firing. So that was why we lost heat for the night.

Once the system kicked on it started working properly again. I think maybe the water heater overheating was due to a faulty aquastat after all. When I took the bulb out of the tank and tested it in 130 degree water it worked, so maybe its a little touch and go. The whole damn system is touch and go.

I worry about the next time I'll be out of heat but at least now I am starting to get a better idea on how to troubleshoot. I am going to get an igniter kit and do some other maintenance. Is it difficult to difficult to clean the heat exchanger because the service guy said I could try to do it myself.

Thanks so much for all the help. Til next time!