Jabsco 12V 25 PSI Par Max 3 Pressure Water Pump - 31395-2512-3A
Product Code: CL31395-2512-3A
The Par Max 3 pressure-controlled water pump comes as a direct replacement for the discontinued model Par Max 2.9 25PSI. This heavy duty model includes a wider diameter motor with a powder coated shell, cast aluminum endbells and lower housing to improve pressure capability and life.
Suitable to serve from 1 to 3 outlets with smooth flow water on demand due to its integrated sealed pressure switch quietly. It can also run dry without damage.
Jasbsco Par Max 3 31395-2512-3A Technical Details
- Moulded diaphragm technology
- Efficient and quiet operation
- Motor protected by automatic thermal overload cut-out
- Includes bypass feature to provide smooth, quiet flow - no need for accumulator tank
- Multi-diaphragm design self primes to 1.8m vertical lift
- Output 11 litres/minute (2.4 gallons/minute) open flow
- Pressure Switch - cuts in at 1.0 bar (15 psi) - cuts out at 1.7 bar (25 psi)
- Connections included for 13mm (½”) bore hose bore Hep20 push-fit connectors CW193
- Fuse size: 10 amp
- Maximum curet 4.4 amps
- Dimensions 230mm long, 152mm wide, 110mm high
What this pump does - and what it does not
Everything below is from Jabsco's own datasheet, linked at the foot of this page. What the pump will not do is set out just as plainly as what it will.
Included
- ✓Three-year Jabsco warrantyBacked by the manufacturer, and worth more here than on the HD4 - see the right-hand list.
- ✓Runs dry without damageJabsco states Run-Dry Capable: Yes. Empty the tank without noticing and the pump survives it - the commonest way a cheaper pump dies.
- ✓Three outlets, on Jabsco's own rule3 GPM against their guideline of 1 GPM per outlet. Galley, heads and a shower.
- ✓It primes from 10 ft3 m of dry lift, further than the much larger HD4 manages. If the pump has to sit well above the tank, that matters more than flow rate.
- ✓The gentler setting25 PSI is easier on older plumbing and quieter than the 40 PSI version, and it draws 5 A against 6 A.
- ✓The 40-mesh strainer is in the boxAlong with both port fittings. Jabsco calls a strainer required in all applications, so it is the one part you should not have to go looking for.
- ✓ISO 8846 ignition protectedApproved for installation in a compartment where petrol vapour can collect. CE and RCM as well.
- ✓1.5 kg, same body as the Par-Max 2More flow for no extra weight or space - the Par-Max 3 is the same physical pump with a higher rating.
Not supported
- ✗No diaphragm kit is offeredJabsco's own service parts list says Not offered against the diaphragm and drive assembly. You can replace the pressure switch, the check valves and the feet, but a perished diaphragm means a new pump. The HD4 is the only family with a published rebuild kit.
- ✗A softer shower than the 40 PSI25 PSI is the gentler setting. If the boat has a shower at the end of a long pipe run, or a filter in the line, the 40 PSI Par-Max 3 is the one to have.
- ✗Intermittent duty onlyEvery Par-Max is rated for intermittent duty, not continuous running. They are built for a domestic water system, where the pump runs while a tap is open.
- ✗Maximum inlet pressure is 30 PSIFine on a gravity or tank feed. If the boat takes a shore water connection, fit a pressure regulator upstream.
- ✗No fuse in the boxA 10 A fuse is specified for this model and is not supplied.
- ✗Three chambers, not fourThe HD4 has four, which gives a steadier flow with less pulsing at the tap. On three chambers you will hear the pump working a little more.
- ✗Parts do not swap with an HD4Different check valve, baseplate and pressure switch. The only part shared across the whole range is the port clip set, 30647-1000.
What you get
Primes from 10 ft
Further than the HD4, which manages 8. Measure the vertical rise from the bottom of the tank to the pump - if it is a long one, this is the pump that works.
Galley, heads and a shower
3 GPM on Jabsco's one-gallon-per-outlet rule. The usual answer for a boat with a shower aboard.
Quiet at 25 PSI
The gentler of the two Par-Max 3 settings, and easier on older plumbing. 5 A against 6 A for the 40 PSI.
Ignition protected
ISO 8846 approved, so it may go in a compartment where petrol vapour can collect. IPX6, CE and RCM.
Reading a Jabsco part number
Jabsco's part numbers look impenetrable until someone shows you the pattern. Take 31395-4012-3A, the 12 V 40 PSI Par-Max 3 - once you can read it, the whole range makes sense in about ten seconds.
31395 - Par-Max 3
The family. 31295 is the Par-Max 2 at 2 GPM, 31395 the Par-Max 3 at 3 GPM. The heavy-duty HD4 uses a completely different scheme beginning Q4.
-40 - 40 PSI
The first two digits after the dash are the pressure switch cut-out. 25 is 25 PSI, 35 is 35 PSI, 40 is 40 PSI. The Par-Max 2 is 35 PSI only.
12 - 12 volt
The last two digits are the voltage. 12 is 12 V, 24 is 24 V. So 31395-4024-3A is the same pump as this one in 24 V.
-3A - range suffix
Constant across the current Par-Max line, and the quickest way to tell a current pump from an older superseded one.
How big a pump do you actually need?
Jabsco publishes one sizing rule and it is refreshingly simple. Everything else is about how hard the pump has to work, how far it has to lift, and whether you can repair it.
Par-Max 2
A galley tap and a basin. Three chambers, polypropylene housings, 1.5 kg. The lightest and simplest pump in the range, and it primes from 10 ft.
Par-Max 3
Galley, heads and a shower. Same body, weight and 10 ft prime as the Par-Max 2, with a higher flow rating and a choice of cut-out pressure.
Par-Max HD4
A bigger boat, or one where the pump has to work. Four chambers, cast aluminium pump head, 2.5 kg - and the only family with a published rebuild kit. Primes from 8 ft, not 10.
The sizing rule
Jabsco's stated guideline is 1 GPM per outlet. Count your taps, including the shower and any deck wash, and buy that many gallons per minute. Then check the lift from tank to pump against the prime figure.
Par-Max 3
Every figure below comes from Jabsco's published datasheet for part 31395-2512-3A.
| Jabsco part number | 31395-2512-3A |
|---|---|
| Open flow rate | 3 GPM (11.3 LPM) |
| Pressure switch cut-off | 25 PSI (1.7 bar) |
| Maximum operating pressure | 25 PSI (1.7 bar) |
| Maximum inlet pressure | 30 PSI (2.1 bar) |
| Chambers | 3 chamber diaphragm |
| Nominal voltage | 12 V dc |
| Voltage range | 9 to 13.6 V dc |
| Maximum current draw | 5 A at 25 PSI (1.7 bar) |
| Recommended fuse | 10 A, not supplied |
| Leads | 305 mm, 16 AWG (1.5 mm2) |
| Motor | TENV permanent magnet |
| Duty cycle | Intermittent |
| Self-priming | Up to 10 ft (3 m) dry prime |
| Run dry capable | Yes |
| Ports | 2 x 1/2 in (13 mm) straight hosebarb |
| Strainer | Inline quick connect, 40 mesh |
| Weight | 3.2 lb (1.5 kg) |
| Fluid temperature | 32 to 140 F (0 to 60 C) |
| Ingress protection | IPX6 |
| Upper and lower housing | Fibre reinforced polypropylene |
| Diaphragm | Santoprene |
| Check valves and seals | EPDM |
| Approvals | CE, RCM, ISO 8846 ignition protected |
| Warranty | 3 years |
| Diaphragm / drive assembly | Not offered |
| Pressure switch kit | 18916-1025 |
| Check valve assembly | 20407034 |
| Baseplate / mounting feet | 20717001A |
| Port clips | 30647-1000 |
Fitting it
- Fit the supplied inline 40-mesh strainer between tank and pump inlet, somewhere you can reach to clean it. Jabsco lists this as required in all applications.
- Use 1/2 in (13 mm) internal diameter flexible hose to keep vibration out of the plumbing.
- Do not overtighten the mounting screws - the rubber feet need to be free to absorb vibration.
- Fuse the supply at the rating in the specification table above. No fuse is supplied with any pump in the range.
- Maximum inlet pressure is 30 PSI, so if the boat takes a shore water connection, fit a pressure regulator upstream.
Ask us before you order
- If it has to fit a known space. Jabsco publishes carton dimensions only. Call us and we will measure one off the shelf for you.
- Certified potable water. If your survey, insurer or charter code requires it, we will find you a pump that carries the certificate.
Par-Max 2 and Par-Max 3
The six lighter pumps. Same body, same 10 ft prime, same 1.5 kg - they differ in flow, cut-out pressure and voltage. Every column links to that model's own Jabsco datasheet.
| Model | Par-Max 2 12 V, 35 PSI | Par-Max 2 24 V, 35 PSI | Par-Max 3 12 V, 25 PSI | Par-Max 3 24 V, 25 PSI | Par-Max 3 12 V, 40 PSI | Par-Max 3 24 V, 40 PSI |
|---|---|---|---|---|---|---|
| You are viewing | ||||||
| Jabsco part | 31295-3512-3A | 31295-3524-3A | 31395-2512-3A | 31395-2524-3A | 31395-4012-3A | 31395-4024-3A |
| Open flow | 2 GPM (7.6 LPM) | 2 GPM (7.6 LPM) | 3 GPM (11.3 LPM) | 3 GPM (11.3 LPM) | 3 GPM (11.3 LPM) | 3 GPM (11.3 LPM) |
| Cut-out pressure | 35 PSI | 35 PSI | 25 PSI | 25 PSI | 40 PSI | 40 PSI |
| Max operating pressure | 25 PSI | 25 PSI | 25 PSI | 25 PSI | 40 PSI | 40 PSI |
| Chambers | 3 | 3 | 3 | 3 | 3 | 3 |
| Dry prime | 10 ft (3 m) | 10 ft (3 m) | 10 ft (3 m) | 10 ft (3 m) | 10 ft (3 m) | 10 ft (3 m) |
| Run dry capable | Yes | Yes | Yes | Yes | Yes | Yes |
| Max current draw | 6 A | 3 A | 5 A | 3 A | 6 A | 3 A |
| Fuse | 10 A | 5 A | 10 A | 5 A | 10 A | 5 A |
| Weight | 1.5 kg | 1.5 kg | 1.5 kg | 1.5 kg | 1.5 kg | 1.5 kg |
| Ingress rating | IPX6 | IPX6 | IPX6 | IPX6 | IPX6 | IPX6 |
| ISO 8846 ignition protected | Yes | Yes | Yes | Yes | Yes | Yes |
| Diaphragm kit | Not offered | Not offered | Not offered | Not offered | Not published | Not offered |
| Pressure switch kit | 18916-1035 | 18916-1035 | 18916-1025 | 18916-1025 | 18916-1040 | 18916-1040 |
| Price | £101.54 £117.35 | £119 £135.88 | £100.71 £123.53 | £111.90 | £97.20 £123.53 | £116.88 |
| Manufacturer datasheet | ||||||
| View product | Par-Max 2 | Par-Max 2 | You are here | Par-Max 3 | Par-Max 3 | Par-Max 3 |
Par-Max HD4
The heavy-duty four-chamber pumps, for a bigger boat or one where the pump has to work. Cast aluminium pump head and a published rebuild kit - but they prime from 8 ft where these prime from 10.
| Model | Par-Max HD4 12 V, 25 PSI | Par-Max HD4 12 V, 40 PSI | Par-Max HD4 24 V, 25 PSI | Par-Max HD4 24 V, 40 PSI |
|---|---|---|---|---|
| Jabsco part | Q401J-112S-3A | Q401J-115S-3A | Q402J-112S-3A | Q402J-115S-3A |
| Open flow | 4 GPM (15.1 LPM) | 4 GPM (15.1 LPM) | 4 GPM (15.1 LPM) | 4 GPM (15.1 LPM) |
| Cut-out pressure | 25 PSI | 40 PSI | 25 PSI | 40 PSI |
| Max operating pressure | 30 PSI | 40 PSI | 30 PSI | 40 PSI |
| Chambers | 4 | 4 | 4 | 4 |
| Dry prime | 8 ft (2.4 m) | 8 ft (2.4 m) | 8 ft (2.4 m) | 8 ft (2.4 m) |
| Run dry capable | Yes | Yes | Yes | Yes |
| Max current draw | 8 A | 10 A | 4 A | 5 A |
| Fuse | 15 A | 15 A | 10 A | 10 A |
| Weight | 2.5 kg | 2.5 kg | 2.5 kg | 2.5 kg |
| Lower housing | Cast aluminium | Cast aluminium | Cast aluminium | Cast aluminium |
| Ingress rating | IPX6 | IPX6 | IPX6 | IPX6 |
| ISO 8846 ignition protected | Yes | Yes | Yes | Yes |
| Diaphragm kit | 18753-0730 | 18753-0730 | 18753-0730 | 18753-0730 |
| Pressure switch kit | 16470-0025 | 16470-0040 | 16470-0025 | 16470-0040 |
| Price | £129.90 | £129.90 | £220 | £220 |
| Manufacturer datasheet | ||||
| View product | Par-Max HD4 | Par-Max HD4 | Par-Max HD4 | Par-Max HD4 |
Choosing a Par-Max
Three questions settle it in most cases, and none of them is about the pump itself.
How many outlets?
Jabsco's guideline is 1 GPM per outlet. A galley tap and a heads basin is two, so a Par-Max 2 covers it. Add a shower and you want 3 GPM. A second heads, a galley, a shower and a deck wash is four, and that is the HD4.
Counting generously is the safer error - an oversized pump cycles less and lasts longer.
How far above the tank?
This is the one people forget. The Par-Max 2 and 3 self-prime from 10 ft; the bigger HD4 manages 8 ft. If the pump sits well above the tank - a deep bilge tank on a motor yacht, say - the smaller pump may actually be the one that primes.
Measure the vertical rise from the bottom of the tank to the pump before you choose.
25 or 40 PSI?
40 PSI gives a firmer shower and copes better with a long run of pipe or a filter in the line. 25 PSI is gentler on older plumbing and quieter, and it draws less current.
If the boat has an accumulator tank, either works well; without one, the higher pressure pumps cycle more noticeably.
What arrives, and what you will still need
Supplied
- Par-Max 3 pump, 31395-2512-3A
- Pressure switch, factory set to 25 PSI
- Inline 40-mesh quick-connect strainer
- 2 x 1/2 in (13 mm) straight hosebarb port fittings
- Quick-connect port clips
- Rubber anti-vibration mounting feet
- 305 mm 16 AWG (1.5 mm2) power leads
You may also need
Jabsco Par-Max FAQs
Can I rebuild it, or is it a throwaway?
Should I have the 25 PSI or the 40 PSI?
Where do the numbers on this page come from?
What about drinking water?
Is a strainer included?
Can I run it continuously?
What happens if the tank runs dry?
Can it go in the engine compartment?
Why does the bigger HD4 prime less than these?
How long is the warranty?
Which fuse do I need?
Not sure which one?
Tell us how many outlets you have and how far the pump sits above the tank, and we will tell you which Par-Max to buy - including when the bigger one is worth it.
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