Two parts, one name.
Many combination boilers, often called combi boilers, use a three way diverter valve to switch between heat and hot water. Other systems use zone valves or an indirect tank, which work differently.
Tub and shower diverter.
- Sits in the tub spout or as a handle on the wall.
- Sends water up to the showerhead when lifted or turned.
- Failure shows as water dripping from the spout during a shower.
- Usually a fixture repair or a spout replacement.
Boiler diverter valve.
- Sits in the boiler or in the piping near it.
- Directs hot water to heating or to domestic hot water.
- Failure shows as no heat, no hot water or odd temperatures.
- A heating repair that needs a plumber or boiler technician.
Signs a boiler diverter valve is failing.
Not every one of these points to the diverter. Air, low pressure or a failed pump can look the same.
Heat but no hot tap water.
The valve may be stuck on the heating side.
Hot tap water but cold radiators.
The valve may be stuck toward the domestic side.
Both lukewarm.
A worn valve can leak between the two paths.
Clicking or humming at the valve.
The motor or actuator may be struggling.
Error codes on the boiler display.
Check your manual, since each maker uses its own codes.
What a homeowner can safely check.
- Look at the boiler pressure gauge and compare it with the range in the manual.
- Check that the thermostat is calling for heat and that its batteries are fresh.
- Make sure the boiler has power and the switch is on.
- Look for water under or around the unit.
- Write down any error code and the time it appeared.
Do not open the boiler cabinet or drain the system. If you smell gas, leave the building and call 911 or your gas utility from outside.
Boiler down in the cold?
Call the emergency line and we will talk you through what to check while a technician is on the way.
Fixing a tub spout diverter.
If the problem is at the bath, check the pull-up knob on the spout. A worn gasket inside lets water slip past it. Many spouts unscrew by hand or with a set screw at the bottom, and a new spout is a simple swap.
When the shower has its own valve with a diverter cartridge behind the handle, replacing the cartridge is the fix. Shut off the water first and take a photo before you start. For deeper leaks inside the wall, our faucet repair page explains when to call. According to the New Jersey Division of Consumer Affairs, you can look up a plumber's license online before you hire, and we suggest you do that for any contractor who opens a boiler.
Older Garfield houses and boiler heat.
Many older houses in Garfield heat with a boiler in the cellar, and many are one, two or three family buildings. In a multi-unit house, ask which tenant or owner controls the boiler before you call, so the visit goes quickly.
If you suspect a leak near the boiler, remember that the Saddle River gauge at Lodi crested at 13.94 feet in September 1999 and 13.5 feet in August 2011, against a flood stage of 6 feet. Cellars in low spots can flood, so keep the boiler and its controls off the floor and ask us about protection.
What a boiler diverter repair visit involves.
Confirm the fault.
The technician tests the thermostat call, pump and valve motor to rule out other causes.
Isolate the system.
Power and water to the section are shut off so the valve can be handled safely.
Replace the part.
The valve body or its actuator is replaced, depending on which one failed.
Bleed and test.
Air is purged, pressure is checked and both heating and hot water are tested.
Repair or replace the boiler part.
For the wider picture, see our boiler repair page. Ask for a written price before work starts.
| Situation. | Repair usually fits. | Bigger fix may fit. |
|---|---|---|
| Actuator motor fails. | Replace the motor head. | Valve body also worn. |
| Valve leaks at the stem. | New seals or valve. | Corrosion elsewhere. |
| Boiler is very old. | Short term fix. | Plan a boiler replacement. |
| Repeated faults. | Check controls and pump. | System upgrade. |
What to tell the technician on the phone.
Say whether you have a combi boiler, a boiler with a separate hot water tank or a steam system. Tell us the make if you know it, and describe exactly what is hot and what is cold. A clear description lets us bring the right valve or actuator on the first visit.
Mention the age of the boiler and any recent work. If the unit has been serviced lately, a past invoice with the model number can save a lot of time. Ask for a written price before work starts, as with any repair.
We handle heating calls in Wallington and Elmwood Park as well. Call (973) 488-5410 and describe what you see, and we will help you tell the bath diverter from the boiler one.
Questions homeowners ask us.
On a combi style boiler it sends heated water either to the radiators or to your taps, so the unit can do both jobs. When it sticks, one side works and the other does not.
No. The spout diverter only redirects water at the bath. It has nothing to do with the boiler, even though the name is the same.
It involves water, power and sometimes gas, so it is a job for a licensed professional. New Jersey requires plumbing work to be done by a licensed master plumber or people working under one.
The diverter may be stuck on the heating side. A failed pump, low pressure or a thermostat issue can look the same, so a technician should test it.
Shut off power to the boiler only if you can reach the switch without standing in water. Call us and a licensed plumber can check the controls before you restart anything.