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Water Heater Repair – Gas Fired Tank Type

water heater repair

Yikes! No Hot Water

Ah the water heater. What would we do without them? Take cold showers? There is one thing I know with certainty, when the water heater stops producing hot water it’s usually a family panic. So here is comprehensive trouble shooting guide to get that water heater up and running again. If you go through the water heater repair steps and nothing works it is unfortunately time to purchase a new one. If you do need a new water heater please consider getting it installed by a trained, licensed plumber. I know that in the age of fiscal responsibility we all want to save a buck by trying to do things ourselves however installing a potential superheated projectile isn’t something to be taken lightly. Try your handy man skills on faucets or a sump pump but leave the dangerous stuff to the pros. Just as a side note the reason I specified Gas Fired Tank Type is because the issues that cause some of the problems are unique to gas water heaters, electric water heaters have their own set of trouble shooting guidelines which I will be sharing with you shortly.

Insufficient Hot Water – There is nothing worse than taking a nice hot shower only to be rudely jolted from our showering bliss with a blast of cold water. Check out this link giving you a break down of the different parts of a water heater.

  1. The Thermostat is set at too low a temperature – This one is simple and it happens all the time, maybe the thermostat was bumped and turned down. Just increase the temperature and you’re good to go. This one was simple
  2. The Heater is Undersized – Maybe the heater you installed when you had small children is too small for the demands of your family now that the kids are teens. It happens all the time. You need a bigger water heater
  3. Sediment or Lime has settled to the bottom of the tank – This is exceptionally common in areas with hard water but it also
    water heater repair

    Yuck. Water Heater Junk

    happens in time in areas with “good” water. Anytime you heat water rapidly dissolved minerals will separate and settle to the bottom of the tank. If your water heater has slowly lost some capacity you may have a 6” layer of sediment on the bottom of the tank. The heat source has to heat the sediment before it heats the water. You can prevent this by draining the heater once or twice a year. If you do have sediment build it is probably like cement because it’s essentially being baked 10 times a day. Time for a new heater.

  4. Heat loss through the water piping – This is extremely rare, it would happen if you put in a 30 gallon water heater in a 10,000 square foot home with plastic water pipe and no insulation. It is more common in commercial buildings where there is a ton of piping with long runs. In these cases having the hot water piping insulated increases efficiency greatly.
  5. Low Gas Pressure – Check to make sure your meter is working properly. Another cause could be that the gas supply line is undersized. Check the heater specs.
  6. You have a leak in the water heater or somewhere in the hot water distribution system. Repair leaks in the system and/or replace water heater.

Pilot Will Not Stay Lit – I think most of us who have dealt with water heaters have experienced this, it’s super common.

  1. Thermocouple is loose or doesn’t work – Snug up the thermocouple or replace it.
  2. The Heater is installed in a confined space like a closet – If the heater is installed in a small utility closet it my not have enough
    This is a confined Space.

    This is a confined Space.

    air/ventilation. In cases like this you only have three options:

  •  Move the heater to a well-ventilated area of the house or building.
  • Replace gas fired with an electric tank-type or tankless water heater.
  • Install louver doors for the closet. Believe us this works.
  1. Backdraft in vent system because of improper vent size or location – Look at the heater requirements for vent size and installation and install correctly sized pipe or change the location.
  2. Inadequate gas pressure – Check incoming gas pressure, you can also check the gas valve to see if the manifold pressure is sufficient.
  3. Lint, Dust or Trash in the pilot burner – This is extremely common especially if the heater is near the laundry area. Lint builds up on the floor and around the heater and there is a natural pulling of air through the burner. With it comes lint and dust. Clean the orifice and surrounding area of trash.
  4. The Flue is clogged – Check the flue and if it has an obstruction remove it.

The burner will not ignite – So in this situation the pilot light is on but the burner will not light to heat the water in the tank.

  1. Debris in the burner orifice – This is very similar the pilot light issue. If the heater is in a spot prone to lint, dust and debris you have
    water heater repair

    This has to be on!

    to maintain the area. Clean burner orifice and attempt to limit debris.

  2. No gas – Check the meter, if there is no gas to your house or business call the utility company.
  3. Gas Valve is not in the proper position – You know the answer to this one. Turn it to the “On” position.
  4. Your Thermostat may be set to low – turn the thermostat to a higher temperature setting.
  5. The Thermostat is broken – Replace the thermostat

Burner flame hovers over the ports – Can you picture this? The there is no flame at the ports they kind of float over the port.

  1. Not enough secondary air – The heater is struggling to find air for combustion. The heater needs better ventilation.
  2. The gas pressure is too high – Call your respective utility company or check the control valve to make sure there is proper manifold pressure.
  3. The Flue isn’t connected to the heater – Reconnect the flue or provide a proper flue connection.

Burner flame is lazy This a plumbing/HVAC term it meaning it’s not a clean burn. The flame is usually yellow.

  1. Not enough of secondary – The heater is struggling to find air for combustion. The heater needs better ventilation.

    water heater repair

    Check the thermostat.

  2. Trash or Obstruction in burner orifice – Clean orifice and check surrounding area for source of debris and remove it.
  3. Low gas pressure – Call your respective utility company or check the control valve to make sure there is proper manifold pressure.
  4. Heater isn’t connected to vent – connect heater to a proper vent.

Drip from the T&P (Relief) Valve or the Relief Valve trips dumping significant water  – You’ve seen this before, a small amount of water is coming out of the relief valve, it may be once in awhile or happening often.

  1. Scale, sediment or lime build up inside the relief valve – This is by far the most common reason for a relieve valve dripping and the T&P needs to be replaced. DO NOT WAIT TO REPLACE.
  2. Thermal Expansion due to heating up water in a closed system – If there is something like a check valve present that is closing
    water heater repair

    Make sure the Drain Tube is Metal

    off the system remove it. Also installing a thermal expansion tank is a very good idea. This gives the water somewhere to expand. It is becoming code in many areas around the US.

  3. Inlet water pressure too high – Install a PRV (Pressure reducing valve) to lower incoming water pressure.

Odors from Combustion – This is a tough one to describe in words but I think most of you have smelled a furnace or burner assembly as it lights. It may smell like paper or cloth burning or there maybe some noxious fumes anyway here are the problems and solutions,

  1. Heater installed in a confined space – Are you seeing a pattern here. Look at the installation requirements for the heater you’re installing and follow them. Those space requirement are accurate believe me, I’ve seen enough malfunctioning heaters in confined spaces to know it’s a real issue.
  2. Water Heater isn’t connected to the vent – Connect to properly sized and installed vent system.
  3. The gas pressure is too high – This causes the heater to over fire or burn to hot. Check the inlet pressure and adjust accordingly.


That about does it. If you have any comments or you have something to add please send me a message and I will add it to the list and reference you in the article. Thanks for reading.


Sean Kavanaugh

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