View Full Version : undermounts

Big John
11-03-2008, 03:19 PM
come on everybody wake up!. in an effort to get a debate going thought i might ask if anyboby has ever seen a good undermount?
i saw a good one last week in a scrap yard which i think is the best place for them but i could be wrong.
Any comments??????

11-03-2008, 06:06 PM
Hi, I'm awake :)

Undermounts, well it's been a very long time since I have seen an undermount fridge. The most common undermount I came across a good few year ago was Carrier M610u and the Carrier Summit, seen a few TK undermounts and some Transfrig units, I think I can vaguely remember a Petter undermount but that is going back, whilst picking my brains on undermount I think the most reliable I came across was a eutectic freezer (frigoblock) on a box van, although it had no diesel engine it was a very reliable nice contraption to work on.

So, back to the topic question, good undermounts, I'm not sure I am in a position to say what was good or not but what I do know is that they all suffered from road muck blocking condensers and radiators and they were generally dirty units to work on. Saying all that though, I did enjoy working at ground level which for me kind of levelled it out.

11-03-2008, 11:16 PM
I sugest you check the HSE web. They are the only
unit they recomend to work on safely.
Ask Morrisons they have just purchased 400.
Also Carrier have the undermounted vector now.
Undermounts are here to stay and the Europa is a reliable piece of kit well proven

12-03-2008, 12:53 AM
Only ever worked on Transfrig undermounts and when you consider how far advanced they were for their time they were incredably reliable. No having to climb up a 15ft ladder to check the water level :eek:

As long as they were serviced/cleaned and 1/2 decent intervals we had no problems



Big John
12-03-2008, 11:08 AM
would agree ground level is good,the old transfrig undermounts are the best i have seen. Can anyboby remember the Vigotrans trailer unit?. It was driven by the trailer axle charging plates, good idea just did not work very well.
The worst undermount ever made has to be the Petter P600U (might be 6500u). truly your worst nightmare.

thermo prince
12-03-2008, 12:23 PM
Hi Big John,
Agree with all 'foresaid comments - ground level working advantage ( read " crawling " or on your hunkers) is more than outweighed by the filth and dirt that low ground clearance throws up onto the subframe and rad/condenser coils.
Dealers should provide free shampoo (or shower caps )to techies whenever despatching them to look at undermounts. What a way to get the " grease lightening' look early on a Monday morning , eh! I remember those Petters p6oou with the ' Oldham ' drive couplings - most of (southern/) fleet was based out at ASDA depot somewhere betweeen Swanley and Dartford.

In Japan due to the strict 30deg " tilt laws" on truck and bus, nosemount units like MD/KD/RD or Supras are just not able to satisfy those Cntr of Gravity requirements.
Hence the evolution of undermount diesel powered units and undermounts are of necessity big sellers there.
<<Bus & coach units for HVAC in Japan also tend to use a lot of Skirt-mount condensers as opposed to Rooftop units popular in Europe & elsewhere - again a lot of "dirt catchers".>>

So called " dog trailers " or drawbars in Europe also aided the development and advance of market ( following on trailer has narrow swing radius clearance to the prime mover body's rear so nosemount again could not be used on the 'dog'.
Dutch flower trucks use a lot and so also Italy is a big market.

Big John or other UK buddys- do you know the whereabouts of Andy Betts (MTK & lived around Hemel Hempstead if I recall?, Dave Playford (MTK & out of old Sittingbourne Kent Depot) or Dave Milburn and "Shirley " both of MTRS down Kent way also ?

best regards

12-03-2008, 07:32 PM
The worst undermount ever made has to be the Petter P600U (might be 6500u). truly your worst nightmare.

To go with the worst normally mounted unit Petter P6-500 :eek:



thermo prince
13-03-2008, 03:59 AM
Was that the one also known as "Coolstream" that held the world record for drive belts & complexity - they used to say easier change belts on a combine harvester than do a set on the Coolstream.:p
The old PDL 50 was not too bad, was a licensed version of the NWD 50.

Where do these old units go b.t.w? Is there a wrecking yard somewhere in UK / Europe - I recall once hearing there was a dismantlers yard in Scotland but imagine there must be many around.
That would be a walk down memory lane to find some of those golden oldies : some of the better samples of vintage TK -Carrier-Petters should be preserved for a museum or collectors club like the car & tractor guys do! :D


Big John
13-03-2008, 01:48 PM
agreed, the p6500 was a dog, it was the beginning of the end for petter. Gray&Adams in Fraserborgh have a collection of old units, they are currantly rebuilding a KL, a unit that had auto stop/start as standard more than 30 years ago.

13-03-2008, 10:30 PM
Yep I Worked On Kl.pt20 Tk Xkw Xrol Xmt And Model M Units Most Trailer And Overcabs Were Propane Or Petrol

thermo prince
14-03-2008, 04:01 AM
Yep I Worked On Kl.pt20 Tk Xkw Xrol Xmt And Model M Units Most Trailer And Overcabs Were Propane Or Petrol

Geeze Skooby, next you'll be telling us you were working on the Model A with Fred Jones himself ;) .... but seriously those XKW (air cooled 2 cyl opposed petrol or gas CCK Onan) / XRW (water cooled RCCK 2 cyl opposed engine) were workhorse units - predecessors of today's KD/RD size machines.
XROL was forerunner to LND type drawbar trailer unit , now filled in that slot by the SL100 types.

Many of those XMT / XKW /XRW still being rebuilt and repowered with Yanmar / Kubota diesels in developing countries plus conversions to 134a.
Do you know where some oldies can be sourced?

Back to the undermounts, the UMD and URD types have gone (somewhat sadly for URD) - been replaced by the UTS unit with scroll and SR control.

Another important global application for undermounts , aside from the large Japan road truck market is on what we call airport catering trucks - hi-loaders or scissors trucks.
For those who are not familiar, take a look around next time you go on vacation or business trip.
You will see them at many airports around the world.
They lift the food carts up and onto the jetliners 747's, Airbus etc.
Condenser section, containing the diesel motor and drive, compressor, condenser + radiator stay down below, mounted on the chassis rails.
Evap , like S2 /3 Spectrums running off dc fan motors are mounted inboard in the catering box which is raised or lowered.
Because the box is 'double entry' for the catering operators , ie roll up doors front and back, the evap needs to be mounted toward centre so as not to run foul of the roll ups.
Connection of suction, liquid and hot gas lines from the condenser section is by combination of flexible hose or " scissors kit" on the hinge points with copper tubing on the straight sections up to the evap.
Electric power for evap fans comes from 12vDC alternator down below, driven by the diesel engine.

regards :)

Big John
14-03-2008, 03:58 PM
Memory lane,,,,,Pleased to see there are still people alive that can remanber the M. Thermo King used a version of the onan cck untill quite recently. It evolved into a performer 220 and was fitted into a bus a/c unit the AMD, We had lots of them in saudi and i have seen them in India.If you are looking for old kit, try Saudi there are still plenty of old NWD clonking away in 45*c ambients. Not bad for units over 30 years old.

Big John
14-03-2008, 05:09 PM
sorry correction to previous note, the performer 220 fitted th AM2 A/C unit, the fore runner to the AMD.
a senior moment!.

thermo prince
15-03-2008, 04:50 AM
Yes , the D in AMD designated Diesel powered whereas the original AM 1 and AM 2 were the petrol/gas powered models. Many of those AM 2were sold to ArAmCo (Arabian American Oil) in the 7o's.
AMD emerged later in the 80's as a convenient 1 piece diesel powerpack unit intended for the Indian and other emerging markets. At that time ancient underpowered Ashok Leyland Leopard 170HP bus engines did not really lend to direct drive of the x430 ( vee belt drive of the prime mover crankshaft). :D
Now that's all changed globally.

Essentially they all were modified self-powered truck units, mounted on rear of bus 'saddle' ( over the engine bay)and blowing air forward through side ducting.

Not sure of the Performer 220 name? Where did you get that from ??? :confused:


Big John
18-03-2008, 01:42 PM
we had trouble getting the engine parts for the am2 in saudi, we could get direct from the onan dealer, i think they were sawari. from onan it was called a 220 performer. they do a whole series of "performer"engines that are still available.

18-03-2008, 03:22 PM
Can anyboby remember the Vigotrans trailer unit?. It was driven by the trailer axle charging plates, good idea just did not work very well.

Very interesting, I do not remember the name Vigotrans, but what I do remember is a transfrig that had hydraulic pump on the trailer axle that drove the compressor up front, I never saw the hydraulic side working, but I did see a later modification whereby the hydraulic pump on the axle was made redundant and a proper gen set was fitted to produce three phase for the electric motor, for old dogs I was surprised they worked as well as they did.

thermo prince
18-03-2008, 03:58 PM
Transfrig and Frigobloc I have heard of but never Vigotrans .... from which country?
What became of them and do they make anything today?

When TK bought over Petter, there were some nice little hydraulic units in the Southampton product line up.
I also felt that Hubbard had useful range of hydraulic drive fridge units for smaller box vans.
I recall seeing many delivery vans and trucks running around London and SE with hydraulic power freezers and they just seemed to run forever.
TK tried the KH 11 hydraulic range, a hydraulic sister of the KD11 diesel but it was pretty short lived.

I often felt we all gave up too quickly on hydraulic drive ( aside from the initial costs of Bosch Rexroth and Volvo pumps & hyd motors) I felt that if initial install and setup was right, those units could run sweet for many years and had many apparent advantages , such as : constant capacity in slow moving traffic or highway, as opposed to the drawbacks of Sanden /Tama ; plus the removal of the inherent weakness of direct drive - the refrigerant flexible hose & fittings running from engine to unit. Yes ,,, hydraulic hose was infinitely more trouble free than refrigerant hose.
Perhaps one of the issues that rang the death bell for the product was refrigeration engineers basically trying to do a plant fitters job - installing hydraulic was probably best left to an experienced guy trained on Hymacs, Cats and JCB. Seriously! ;)
Anyhow ,,, chapter is over now and hindsight is 20:20 they say. What do/did others think of hydraulic units.


19-03-2008, 10:54 PM
Yes i worked on Petter HPA units they had Sunstrand
Pumps running off the pto on the truck gearbox.
HOB Then the HY.
The Inverter is the latest phase of small truck drive
to get away from direct drive units hose and compressor failure

Big John
20-03-2008, 04:21 PM
the full name of the vegotrans was,,, vigotrans eutec.
seem to think they were dutch. mtk in cambs. fitted a number in the mid 80"s. BRS Roadservices ran them on the Birds eye contract. they were driven by a power pack,not by the trailer axle as previously stated, think that was a transfrig. they did not last long and were scrapped fairly quickly. Remember the HY well it was a nice little unit as were a lot of the petter units.
Hydrolic or Refigeration hose it seems pretty much the same, personally feel that Frigoblock have got it about right the truck units work well, lots of capacity.
As a tk man it hurts to say it but they are nice bits of kit..

thermo prince
20-03-2008, 04:56 PM
Dont see a lot of the Frigoblock on this side of the globe ( read 'none') but I personally agree that 'electric' drive is the way to go ultimately for truck refrig and coach a/c.
But it needs a 'breakthrough' in technology.

Last time I worked in Europe, memory of FrigoBlock was massive alternators, l( big like workshop 3ph motors) 'dangling' off prime mover crank pulleys - not a small load indeed on a petrol / diesel motor of ~100BHP or less.
Many almost with no ground clearance. Alternator ouput & Hz was proportional to the engine rpm.
Inverter-converter technology to try and give steady state Hz regardless of idling @500 engine rpm in London traffic jam or belting around the M25 @ circa 3000erpm on a diesel Transit or Iveco, was and still is the challenge.
<< ignoring 'driver <->driven pulley' ratios for the purpose of discussion, of course>>
Don't know that anyone has solved reliably or made something that endures.
Also with todays engines with turbo, intercoolers, power steering, common rail, 12v or 24v chassis alternators - we are challenged in this crowded arena to find a space to fit an additional 'lump' yet alone find a free drive sheave off the crank pulley to drive it!

TK withdrew for present, the A1100 which had a 10kW water cooled alternator with heaps of state of art inverter-converter tech. That could pull -29C box temp in 28~30 ft rigid bodies in high ambient.
Price, complexity and market demand - simple fact is your typical 'Fred the butcher ' down the village likes plain vanilla diesel powered (SP Truck) or direct drive (OED)Tama/ Sanden compressor type units still.
Same with cryo - it's time has not yet arrived.

Thinking more of the Vigotrans: if trailer axle drive originally, then that was no better than 'ground speed p.t.o. on farm machines - no movement or forward velocity, then no drive to hyd pump or compressor, hence no refrigeration effect! Not a lot of good if stuck on M25 gridlock with ice cream load rapidly starting to drip out the back door :eek:


Big John
25-03-2008, 04:51 PM
not an expert by any means only see them now and again but they seem to be very reliable, the mount kits are good and seem to be available for most trucks. Think you need to be upwards of 7 ton.think the biggest problem is the initial cost of the unit and install. There sales people are pretty cute they always over spec, have never spoken to a customer with temp. issues using Frigoblock, not to say there are non, could be others may know differant.?
i well remember the A1050. TK'S very own P6500. Titanic springs to mind.

30-03-2008, 05:09 AM
I have an UTS in my shop right now. It doesn't scare me at all. As a matter of fact, I will make lots of money when I have to drop ot to change an alternator belt. What usualy takes 5 mins. now takes 2 hours. Love it $$$$$$$
I am putting never seize on everything now before we install it.;)

30-03-2008, 07:25 PM
Undermount units in my area are short lived due to road salt and magnesium chloride to remove snow and ice from the roads. pretty much all the stuff that reacts and causes oxidization on steel and aluminum and copper.

02-04-2008, 06:00 AM
Undermount units in my area are short lived due to road salt and magnesium chloride to remove snow and ice from the roads. pretty much all the stuff that reacts and causes oxidization on steel and aluminum and copper.
That and eggs! hahahaha:D

02-04-2008, 02:49 PM
That and eggs! hahahaha:D

Oh yeah,, and of course lets not leave out the eggs:D