Hot water heater issues

There is plenty to go wrong here, but you can repair it
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Hot water heater issues

Post by kevm14 »

Over a period of several months, we'd lose hot water and the fix was to press the reset switch on the oil burner. This would happen as frequently as once a week or go a much longer period. Today it happened repeatedly - it wouldn't even light off.

I guess I figured out what that circuit is doing. When the thermostat calls for heat, the burner fires up. First the fan, then the igniter (like a spark plug) and then oil injection (the fan and oil injection may happen at the same time). In this case, I could hear that there was no flame. It was just injecting oil into the firebox. Great. So when I reset it, it would try to run and after 5 seconds or so of no flame, it would shut itself down.

I almost gave up right there and called for service, as I think it is due anyway.

But I got bold and decided to open up the transformer assembly.
WP_20151121_15_53_35_Pro.jpg
Just loosen these two screws and the retainer plates swing out of the way.
WP_20151121_15_53_45_Pro.jpg
The transformer is on a hinge, and this is the label plate. Yes, 10,000 VDC.
WP_20151121_15_54_22_Pro.jpg
So this is pretty simple. Those springs make contact on the rods and that carries the voltage/current to the igniter which is probably pretty close to the injector. Think of it like a flame thrower.
WP_20151121_15_54_28_Pro.jpg
I took some sandpaper and sanded both the springs and the rods, which you can see here:
WP_20151121_15_54_36_Pro.jpg
WP_20151121_15_54_41_Pro.jpg
I put it all back together and it fired right up.

I will definitely be keeping my eye on it as there could be other reasons the flame doesn't ignite (the transformer itself and the control circuitry mainly).

At least this is all based on my understanding of how it works. I guess I could go look it up online, but that's boring.

By the way, this is only a 30 gallon tank and I basically have unlimited hot water. The burner capacity on this, compared to a gas unit, is considerably higher. It's got enough capacity that, during a shower, it will kick on, get the water back up to 130°F and actually shut off again. DURING a shower.

The rating is 118 GPH (gallons per hour) at 100°F temperature rise. So if the water coming out of my well was 45°F, it could make 145°F water at a rate of 2 gallons per minute. Since it only needs an 85°F rise, I'd estimate 2.35 GPM, continuous. My shower head is rated at 2.0 GPM max (I think at 80 psi). My well water pressure never gets that high, so figure 1.75 GPM. 1.75 / 2.35 ~= 75% duty cycle (6 minutes on, 2 minutes off, etc.). So there's the math on why the hot water heater can actually cycle during a shower. Yay.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

Probably should have mentioned that the ignitor failed a few years ago and Exeter Fuel did an overhaul on the burner. They replaced the nozzle, ignitor, and rebuilt the fuel pump (and a new filter of course). Knowing what I know now, I think I could have gotten away with simply replacing the ignitor as I did on my furnace and saved a couple hundred bucks. They are on the shelf at Home Depot and very easy to replace.

Since then I did some work on my furnace but the hot water heater just sat. This weekend I finally serviced it.

General work performed:
- Remove and inspect nozzle assembly. It is a 0.75 and I think 80A but I should confirm. I didn't replace as I have yet to actually replace a nozzle (I have done all of the work to get to the nozzle in the furnace and hot water heater but have simply not bought replacement nozzles yet).
- Vacuum/clean burner and inside of hot water heater. It wasn't that bad but had some sediment on the bottom. This has precisely zero impact on anything as the tank is above the flame area obviously.
- Replace filter

Put it all back together, bled, and works fine. I should consider getting nozzles because I assume they don't last forever - I think the small pre-filters may clog or the tip otherwise gets cruddy and the spray pattern becomes wonky. In my experience they last far more than 1 year though. Same with the filters. Annual replacement seems excessive though annual inspection and cleaning seems like a good idea.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

Time for a new hot water heater...

Lack of hot water even as it is running. It is hotter than it should be externally so that is a classic sign of excessive scale/sludge/buildup in the inside. I flushed the T&P valve as well as the drain valve. Neither are that hot. The drain never seems to stop producing rusty looking water. So....yeah. I think it is 22 years old. It is a direct fired oil burner tank. I'd probably like to keep this style as they make unlimited hot water (well usually). I also need to move it across the basement and power vent it out the side to get it off the chimney. Theoretically we'd finally pass the draft test and assuming there are still subsidized insulation installations, finally get that done.

I don't want the modern high efficiency ones that use a heat pump and electric elements. NOT generator friendly and do not recover like the big nasty oil burner units. Efficiency is not a big deal since it goes all summer on one tank. The furnace is the big oil user.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

This may be a newer version of my model.
https://www.supplyhouse.com/Bradford-Wh ... -Rear-Flue
High Recovery Rates - Oil heats water 3 to 4 times faster than other methods. These models are designed to assure a constant supply of hot water provided the draw-off rate is within the recovery capacity of the unit. Center flue models from 32 to 50 gallons capacity delivery recovery rates as high as 110 gallons per hour. Rear flue models are designed for heavier demand with recovery rates as high as 195 gallons per hour.
Mine is rear vent. And damn right. Those recovery rates are ridiculous. No wonder why it is only 30 gallons and never runs out.

Mine is an RF-30.

Production may have ended in 2014, however. Hopefully I can still get something of similar quality. The AO Smith ones at Home Depot have horrible reviews and I believe that brand is not great...
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

http://www.mannionpetroleum.com/oil-fir ... r-heaters/

There is a sanctioned power venter, too. Maybe I can still get Aero.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

I am not sure these are still available. I don't see anything on the Bradford White website about oil fired hot water heaters. FFS!
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

Even though I can probably swap the oil burner to the new tank, apparently even just the tanks are pricey.

http://www.jupiterheating.com/bock-wate ... tanks.html

Looking at $1,300 for a high quality replacement. Plus power venter. Plus installation. I'd think this is going to run like $2,000 and possibly more. Damn.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

Upon closer look I am not sure I can even get one at Home Depot even if I wanted to. It will go up my ass if there is some regulation that prevents me from buying a replacement oil fired hot water heater.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

This is a bit of a hail mary pass, but I am going to attempt to flush it by draining it completely and letting the junk at the bottom of the tank hopefully come out. If I am REALLY lucky, functionality will improve enough to buy a few months...

Aside from regular anode replacement (which no one does, ever), you can also flush these periodically. This seems like changing the trans fluid on a slipping high mileage trans. It can temporarily add service life.

https://www.aaaheatingandcoolinginc.com ... er-heater/
The frequency with which to flush a water heater depends on the size of the tank and the amount of hot water used. It is a good idea to refer to the manufacturer’s instructions. Usually, the more hot water a household uses, the greater the maintenance flushing frequency.

With time, water heater sludge accumulates at the bottom of a tank as minerals, sediment and other deposits settle in the water. Flushing out these deposits prolongs the heater’s life and prevents malfunctions, such as cold bursts of water.

If you don’t have access to the manufacturer’s instructions, the following serves as a general guide:
One or two people in a home: Inspect the water heater every six months and drain it every 12 months
Three to five people in a home: Inspect the water heater every four months and drain it every eight months
Six or more people in a home: Inspect the water heater every four months and drain it every six months

You may need to drain the hot water tank more often if your water comes from a well or if your municipal water has abnormally high sediment content.
Damn. Well I'm super impressed this thing has lasted this long under unfiltered well water conditions!

Now that said I have flushed into a bucket before and also do so at least annually on my other house. But draining is something I've never done and in this case is probably warranted to see if I can get some of the junk off the bottom of the tank. Worth a try I think...since it isn't leaking yet a good flush could restore some heat transfer and prevent actual damage from occurring. Wouldn't that be something...
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Hot water heater issues

Post by kevm14 »

Drained. Flushed and rinsed and drained some more. Lots of rust and it eventually cleared. It is running now. We'll see how it goes.

I must have dumped 40 buckets outside to drain. I could have used a hose since I have a walk-out but I wanted to see in the bucket I guess. Next time I will use a hose and stick it into a bucket for a second to see the color or something.
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