Advocate Blog

Excessive Water Pressure

Thermal Expansion Tanks

Thermal expansion tanks prevent excessive water pressure build up from your hot water heater. This is basic plumbing knowledge if you’re a plumber. But since moving to Lees Summit I find myself frequently explaining this to my plumbing customers. So lets explore it.

What is thermal expansion

Water heaters don’t just heat your water. They also create pressure. When you heat water it expands. When it expands it wants to move backwards through the water pipes. But if you have something blocking this backward water flow the expansion will quickly create pressure. That’s thermal expansion.

What is a thermal expansion tank

A thermal expansion tank is a small tank, usually three to five gallons, that attaches to the cold water inlet pipe of your water heater.

excessive water pressure, leaking water heater, relief valve
Thermal expansion tank cutaway

Inside the tank is a rubber bladder that’s pressurized with air. So on one end of the tank is the rubber air bladder. And on the other end is a water connection. When connected to your hot water heater, water will push against the rubber bladder inside the expansion tank. The water pressure and air pressure should be equal. This will create a static cushion. When thermal expansion occurs it will allow the water room to expand instead of building excessive water pressure.


Do I need a thermal expansion tank

The ONLY time you need a thermal expansion tank on your water heater is when there is a device blocking water from flowing backwards in your water pipes. And even then, these devices could have bypass valves installed to allow for thermal expansion. That’s where the judgement of your plumber comes into play. The only such devices most Lees Summit homeowners will come across are water pressure regulating valves and check valves.

Lees Summit hot water heater, thermal expansion tank
How thermal expansion tanks work

A quality water pressure regulating valve will have a built-in bypass valve. This valve will allow water that exceeds city water pressure to bypass the valve and flow back into the city water supply. But if the city water pressure is too high this bypass won’t help much.

A check valve is sometimes installed on a water meter by the city. They do this to protect the drinking water system from back-siphonage. You’ll definitely need a water heater thermal expansion tank in this circumstance. But there are some symptoms of thermal expansion for which you can check.

Symptoms of thermal expansion

Finding thermal expansion in a home usually isn’t too difficult. The first place I look is the water heater. An intermittently leaking water heater relief valve is a sure sign. The relief valve will eventually stick open and leak all the time.

A sudden surge of faucet water pressure that quickly dissipates is another sign to look for. If you have a solid plumbing system with no leaking fixtures or appliances, pressure builds up. When a faucet or toilet is used this pressure quickly equalizes.

The usual signs of excessive water pressure are also to be expected. This could mean banging pipes, high water velocity noises or plumbing fixtures or appliances wearing out too soon.

Who installs thermal expansion tanks

Plumbers install thermal expansion tanks. You’ll hear air conditioning and heating contractors or handymen advertising for them. But many times they don’t know how they work. You wouldn’t hire a landscaper to work on your car. Only hire a plumber to work on your plumbing. Call your local Lees Summit hot water heater specialists at Advocate Master Plumbing. We not only know how to install plumbing. We know how and why it works.

Water Heaters

Retrofit Hot Water Heat Loop

In this post we’re going to discuss the retrofit hot water heat loop. Previously we’ve discussed two types of hot water heat loops: Standard hot water heat loops & Gravity hot water heat loops (Thermosyphons). There is a 3rd option that can be installed in any home. It’s the retrofit hot water heat loop. Many of my Lees Summit plumbing customers are enjoying instant hot water because of this system.

What’s retrofit hot water heat loop mean?

Retrofit means to add to something that’s already been manufactured. In this case, it means to add a hot water heat loop to a home that’s already been built. This implies that the plumbing system wasn’t originally designed for the heat loop. A retrofit heat loop can be installed regardless of the homes design. The most commonly installed brand in Lees Summit is the Grundfos Comfort System.

The Grundfos Comfort System

A Grundfos Comfort System is a standard hot water heat loop without the extra pipe. There’s no need to install a pipe from the bottom of the water heater to the furthest hot water fixture in your home. Instead, a low flow hot water recirculating pump is installed on the hot water side of your existing water heater. Then the hot and cold water pipes are connected at the furthest plumbing fixture using a bimetal blade bypass valve. This system enables any homeowner to install a hot water heat loop.

Hot water heat loop, retrofit
Grundfos Comfort System


Pros & Cons of the Grundfos Comfort System

The Pros of the Grundfos Comfort System are the reason for it’s popularity over the years. Those are:

  • Instant hot water
  • Water waste is minimized
  • No need for access to the plumbing pipes
  • No need to insulate the hot water pipes
  • The low wattage pump uses very little electricity
  • A whisper quiet pump with a built in timer

retrofit hot water heat loop

And the Cons are:

  • Initial upfront cost ($850 – $1,100)
  • An outlet is needed near the water heater
  • Bypass valves need replacing every few years
  • Cold water side of fixture with bypass valve has a short burst of warm water

Where to get a retrofit hot water heat loop system

The Grundfos system can be purchased online, at many home stores or professional plumbing supply stores. But due to the type of skill needed to install the pump, you better leave it to the plumbing professionals to install the system. It’s a pretty straight forward install. But a lot can go wrong if you don’t have the plumbing chops to handle it. So call Advocate Master Plumbing. We’re your local Lees Summit hot water heater specialists near you.


Water Heaters

Standard Hot Water Heat Loop

After moving to Lees Summit, Missouri I needed to install a hot water heat loop. My wife didn’t want to wait for the water to get hot at the kitchen sink faucet. My house was already built but I had a basement and access to all the water piping. So of the three options for a hot water heat loop I chose a thermosyphon. However, if you have a new home build or an unfinished basement, you can install a standard hot water heat loop.

hot water heat loop, Lees Summit Plumber, hot water pump
Standard hot water heat loop

3 Types of Hot Water Heat Loop

We began this discussion in my previous post. Generally, there are 3 types of hot water heat loop. Without wandering into solar energy or wind energy these three options are the most common.

  1. Standard hot water heat loop – An extra hot water pipe & pump.
  2. Retrofit hot water heat loop – A pump with a cross connection on hot & cold water pipes.
  3. Thermosyphon – An extra hot water pipe circulating hot water using convection.

Standard heat loop

In this post we’ll be discussing the standard heat loop. For this type of hot water heat loop you’ll need access to all hot water pipes. These are usually installed during home construction.

Standard hot water heat loop construction

In a home there is normally a cold water pipe that enters the home from the city utility provider. From this point it’s distributed throughout the home. Where hot water is needed the cold water will be directed into a heating appliance such as a hot water heater. From there the water will be heated and a second configuration of piping will distribute hot water to various plumbing fixtures.

Standard heat loop components

A standard heat loop is installed at the base of the water heater & run to the point of usage; usually the furthest plumbing fixture from the water heater. To install this you’ll need the following:

  1. A hot water pump
  2. An extra run of piping
  3. A check valve
  4. Two water shut offs
  5. Various pipe connections

For any of these parts you can go to Reeves – Wiedeman plumbing parts.

How a standard hot water heat loop is installed

At the base of a water heater is a drain valve. You’ll need to install a tee connection between this drain valve and the water heater. Then install a water shut off on the tee’d branch. Then, in a horizontal direction of flow install a check valve. This will prevent inadvertent backward flow. Then the hot water pump is to be installed. Then a second water shutoff is to be installed. The check valve and pump are between the water shut offs so that maintenance may be performed as needed. Then the pipe is run to the furthest plumbing fixture. The pipe is tied into to the hot water pipe closest to the furthest fixture.

How a hot water heat loop works

A heat loop is a second hot water pipe that leads from the furthest plumbing fixtures hot water pipe to the base of the water heater. A pump will draw water from the hot water pipe and circulate it toward the bottom or coldest part of the water heater. This will maintain the temperature in the main hot water pipe and therefore allow almost instant hot water at that particular plumbing fixture. And the other hot water branch lines will get hot faster when used. The check valve will prevent backward flow if a pump fails or during maintenance. The water shutoffs will allow for maintenance without draining the water heater.

In Conclusion

I never realized how much water I wasted when waiting for the kitchen faucet to get hot. And the other plumbing fixtures get hot much more quickly too. A hot water heat loop is good for the environment. It also saves money. Does it pay for itself? I don’t know. But I think so. But even if it doesn’t it’s a luxury that is good and is justified. If you find yourself waiting too long for the water to get hot give your local Lees Summit plumber a call. We’ll save you money and improve the efficiency of your hot water heater system. Advocate Master Plumbing is the homeowners advocate.

Gas Water Heater

Lees Summit Heat Loop

Since moving our plumbing service business to Lees Summit, Missouri we’ve tried to downsize our home. Since the business is run out of our home a lot of organization has gone into it. The first of many upgrades to the smaller house I made was to upgrade the water heating system.

I’ve never been a fan of large water heaters. They tend to be a lot of unnecessary upfront expense. And I don’t feel there’s enough value to justify it. I prefer a dual standard tank style water heating system. It’s simple. And if there’s ever a need for maintenance and I’m not around my wife can find help easily.

Dual water heater installation

Installing the dual State 40 gallon natural gas water heating system was pretty straight forward. I opted to install it with both hot and cold water shutoffs in a parallel piping configuration. This allows for hot water to be drawn from both tanks at the same time equally. It also allows us to shut off one water heater in the case of tank failure without losing hot water.

Thermosyphon, hot water recirculating loop, instant hot water
Dual water heaters with thermosyphon

Hot water recirculating options

The next project was installing a hot water loop. I’ve installed hot water recirculating loops before that involved a pump. Some were installed at the time of the home being built. This allows for a pipe to be run to the furthest fixture. But these use a lot of electricity.

And some were retrofitted. They needed special bimetal connectors that cross connect the hot and cold water pipes. But these needed maintenance every few years. They also introduce a little warm water to the cold water side of a plumbing fixture.

I wanted a maintenance free option that was good for the environment. I also wanted a hot water heat loop my wife wouldn’t have problems with if I wasn’t around. So I installed a thermosyphon.

Thermosyphon installation

A thermosyphon is a gravity heat loop. I just like saying thermosyphon. I feel smart when I do. But it’s pretty simple. A thermosyphon is a passive hot water recirculating pipe using convection. A hot water pipe is connected to the bottom of the water heater. It’s then connected to the point in your home that you want instant hot water. In our case it was the kitchen sink.

After running the extra pipe you insulate the whole pipe except for the last 15 feet closest to the bottom of the water heater. Then insulate all the hot water pipe starting at the top of the water heater and ending at the fixture. This will create a situation in which all the hot water pipes in that loop will be hot except that last 15 feet. Since cold water is heavier than hot water, the cold water will fall to the bottom of the water heater. This will push the hot water toward the fixture in the loop. Once the “engine” is started it will run continually.

Benefits of the thermosyphon

The results are instant hot water at our kitchen faucet. We can now turn on our dishwasher and know that it’s hot water cleaning our dishes and not the cooled water that’s in the hot water line due to no recent use. We use a lot less water since we don’t let it run until it’s hot. And there’s no pump. I don’t know the exact figures but I’m sure that the savings on water more than makes up for the extra hot water heating due to the uninsulated section of the heat loop and constant heating of hot water.

Not everyone is a candidate for a thermosyphon. If you have no basement or don’t have enough access to your water pipes, you’ll have to be happy with a hot water recirculating pump. But there are options. There will be more about this on my website plumbing services page later.

Lees Summit hot water recirculating systems

For now, I’ll just say that Lees Summit has been very good to my family and my business. And I’m very grateful. I look forward to serving my plumbing customers and neighbors. And hopefully can offer this new hot water recirculating service to them. For more information about our water heater services go to our water heater services page or water heater DIY page under water heaters.